%D \module

%D \module
%D [ file=ppchtex (m-chemie),
%D version=1997.03.19,
%D title=\CONTEXT\ Extra Modules,
%D subtitle=\PPCHTEX\ (Plain Pictex Context cHemie \TEX),
%D author=Hans Hagen,
%D date=\currentdate,
%D copyright={PRAGMA / Hans Hagen \& Ton Otten},
%D suggestions={Tobias Burnus, Dirk Kuypers \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

% option=test => boxes
% dummy => file
% final => file / local run
%
% constante van phantom in definitie ONE: \setchemicaltextwidth 300
%
% it would be interesting to rewrite this module with todays
% experiences and new context functionality, mybe ...

% Deze module ondersteunt het zetten van chemische
% (structuur)formules. Hoewel de macro' zijn afgestemd op
% CONTEXT, zijn ze ook buiten deze zetomgeving te gebruiken.
%
% Dit is, afgezien van updates, de definitieve versie van
% PPCHTEX. Gebruikersgemak, eenvoud, flexibiliteit, en
% snelheid zijn inmiddels redelijk geoptimaliseerd. Dit neemt
% niet weg dat hier en daar nog verbetering mogelijk is. Dit
% zal dan ook nog gebeuren.
%
% Volgende versies zullen tenminste dezelfde functionaliteit
% hebben. We houden ons natuurlijk het recht voor de kwaliteit
% van de output te verbeteren. Daarnaast staan nog op het
% wensenlijstje:
%
% - optimaliseren in termen van proces-tijd
% - aanpassen naamgeving van interne macro's
% - toevoegen van functionaliteit
% - in \x!-vorm omzetten van GIVES, TB enz.
%
% De mix tussen engels en nederlands lijkt soms verwarrend.
% Meestal zijn verborgen macro's engels en zichtbare macro's
% nederlands. Het gebruik van [ ] en { } sluit aan op andere
% Context-macro's. Hetzelfde geldt voor instellingen en
% \start-\stop-constructies.
%
% De schijnbaar overbodige \bgroup-\egroup constructie
% garandeert aansluiting bij de Context-macro's voor het
% plaatsen van figuren, tabellen en andere floats.
%
% Binnen Context worden de macro's geladen met
% \gebruikextras[chemie]. Daarbij wordt een passende melding
% getoont. Buiten Context genereren we een melding:

\doifundefined{usemodule}
{\writestatus{loading}{Context Chemical Macro's / 1996.3.1}}

% Er kan gebruik worden gemaakt van PiCTeX of PStricks. Een
% van deze pakketten moet van te voren zijn geladen.
%
% \input prepictex.tex (i.g.v. LaTeX)
% \input pictex.tex
% \input postpictex.tex (i.g.v. LaTeX)
%
% of:
%
% \input multido.tex
% \input pstricks.tex
% \input pst-plot.tex
%
% In \CONTEXT\ kan men de modules m-pictex en m-pstricks
% gebruiken. De eerste module laad of efficiente wijze PiCTeX
% en de tweede module koppelt het PSTRICKS kleurmechanisme
% aan dat van \CONTEXT.
%

% PSTricks: {-\chemicalangle} instead of {*0}, which produces
% faulty ps code when \chemicalangle=0

\startcommands dutch english german

gotochemical: naarchemie gotochemical zurchemie
setupchemical: stelchemiein setupchemical stellechemieein
startchemical: startchemie startchemical startchemie
stopchemical: stopchemie stopchemical stopchemie
definechemical: definieerchemie definechemical definierechemie
chemical: chemie chemical chemie
toptext: boventekst toptext textueber
bottext: ondertekst bottext textunter
midtext: middentekst midtext textmitte

\stopcommands

\doifundefined{fiverm} % In the more recent LaTeX versions
{\font\fiverm=cmr5 } % \fiverm is no longer (pre)defined.

\doifdefinedelse{beginpicture} % PiCTeX
{\doifdefinedelse{startMPdrawing}
{\chardef\chemicaldrawingmode=2 } % MetaPost
{\chardef\chemicaldrawingmode=0 }} % raw
{\doifdefinedelse{psaxes}
{\chardef\chemicaldrawingmode=1 } % PSTricks
{\chardef\chemicaldrawingmode=3 }} % unknown

\ifcase\chemicaldrawingmode
\writestatus{ppchtex}{using PiCTeX}
\or
\writestatus{ppchtex}{using PSTricks (still experimental)}
\writestatus{ppchtex}{automatic sizing not (yet) supported}
\or
\writestatus{ppchtex}{using PiCTeX and MetaPost}
\else
\writestatus{ppchtex}{load PiCTeX (+pre/post) or PSTricks (+pst_plot) first}
\bgroup
\read16 to \exit
\egroup
\expandafter\endinput
\fi

% De onderstaande help-informatie (%I) kan worden opgeroepen
% in TeXEdit. De daaropvolgende setup-informatie (%S) kan
% nadat zij is uit deze file is gefilterd met TeXUtil, in
% handleidingen worden gebruikt. In deze file opgenomen
% documentatie (%D en %M) kan worden gebruikt voor een
% technische handleiding. Met %T kunnen templates worden
% gedefinieerd voor TeXEdit.

%I n=Chemie
%I c=\stelchemiein,\chemie
%I
%I Chemische formules kunnen worden gezet met behulp van de
%I onderstaande commando's:
%I
%I buiten $ en $$ :
%I
%I \chemie[segmenten][symbolen]
%I
%I \startchemie[instellingen]
%I \chemie...
%I \chemie...
%I \stopchemie
%I
%I en binnen $ en $$:
%I
%I \chemie{}{}
%I
%I Voor tekst, uitleg en voorbeelde verwijzen we vooralsnog
%I naar de handleiding.
%P
%I Het gedrag van de macro's kan worden ingesteld met:
%I
%I \stelchemiein[breedte=,hoogte=,links=,rechts=,boven=,
%I onder=,korps=,schaal=,status=,assenstelsel=,kader=,
%I variant=,optie=,formaat=,tekstformaat=,resolutie=,
%I offset=,letter=]
%I
%I Structuren kunnen worden voorgedefinieerd met het commando
%I
%I \definieerchemie[naam]{\chemie...}

%S \startsetup
%S \command
%S [\!stelchemiein]
%S \type
%S [\c!vars!]
%S \variable
%S [\c!breedte]
%S [\c!number!,\v!passend]
%S [0]
%S \variable
%S [\c!hoogte]
%S [\c!number!,\v!passend]
%S [0]
%S \variable
%S [\c!links]
%S [\c!number!]
%S [0]
%S \variable
%S [\c!rechts]
%S [\c!number!]
%S [0]
%S \variable
%S [\c!boven]
%S [\c!number!]
%S [0]
%S \variable
%S [\c!onder]
%S [\c!number!]
%S [0]
%S \variable
%S [\c!resolutie]
%S [\c!number!]
%S [\outputresolution]
%S \variable
%S [\c!korps]
%S [10pt,11pt,12pt]
%S [\bodyfontsize]
%S \variable
%S [\c!schaal]
%S [\v!klein,\v!middel,\v!groot]
%S [\v!middel]
%S \variable
%S [\c!formaat]
%S [\v!klein,\v!middel,\v!groot]
%S [\v!groot]
%S \variable
%S [\c!tekstformaat]
%S [\v!klein,\v!middel,\v!groot]
%S [\v!groot]
%S \variable
%S [\c!status]
%S [\v!start,\v!stop]
%S [\v!start]
%S \variable
%S [\c!kader]
%S [\v!aan,\v!uit]
%S [\v!uit]
%S \variable
%S [\c!assenstelsel]
%S [\v!aan,\v!uit]
%S [\v!uit]
%S \variable
%S [\c!optie]
%S [\v!test]
%S []
%S \variable
%S [\c!variant]
%S [1,2]
%S [1]
%S \variable
%S [\c!offset]
%S [HIGH,LOW]
%S [LOW]
%S \variable
%S [\c!letter]
%S [\c!command!]
%S [\rm]
%S \stopsetup

%S \startsetup
%S \command
%S [\v!startchemie]
%S \type
%S [\c!vars!\c!stp!]
%S \inheritvariable
%S [\v!stelchemiein]
%S []
%S \stopsetup

%S \startsetup
%S \command
%S [\v!chemie]
%S \type
%S [\c!vals!\c!vals!]
%S \value
%S [\c!list!]
%S []
%S \value
%S [\c!list!]
%S []
%S \stopsetup

%S \startsetup
%S \command
%S [definieerchemie]
%S \type
%S [\c!val!\c!arg!]
%S \value
%S [\c!text!]
%S []
%S \stopsetup

\unprotect

% Om te voorkomen dat sub- en superscripts botsen passen we
% wat fontdimen's aan (Knuth, The TeXBook, p179). Helaas
% kunnen deze instellingen niet lokaal worden gehouden door
% groeperen, vandaar dat een en ander moet worden geset �n
% gereset.
%
% Er dient een relatie te worden gelegd met de afmetingen
% van de letters. In een eerdere versie werden daartoe de
% \fontdimen's opgehoogd. Omdat dit problemen gaf bij
% scaled fonts, is bij nader inzien gekozen voor de
% onderstaande oplossing, waarbij de nieuwe waarden worden
% afgeleid van de x-height (\fontdimen5). De factor 0.70
% is min of meer experimenteel vastgesteld. Soms worden de
% regels iets verder uit elkaar gezet. Jammer. Italic fonts
% hebben grotere cijfers en vallen min of meer uit de boot.

\newif\ifloweredsubscripts

% Due to some upward incompatibality of LaTeX to LaTeX2.09
% and/or LaTeX2e we had to force \@@dochemicalstyle. Otherwise
% some weird \nullfont error comes up.

\def\beginlatexmathmodehack%
{\ifmmode
\let\endlatexmathmodehack=\relax
\else
\def\endlatexmathmodehack{$}$\@@dochemicalstyle\empty
\fi}

\def\setsubscripts%
{\beginlatexmathmodehack
\def\dosetsubscript##1##2##3%
{\dimen0=##3\fontdimen5##2%
\setxvalue{@@\string##1\string##2}{\the##1##2\relax}%
##1##2=\dimen0\relax}%
\def\dodosetsubscript##1##2%
{\dosetsubscript{##1}{\textfont 2}{##2}%
\dosetsubscript{##1}{\scriptfont 2}{##2}%
\dosetsubscript{##1}{\scriptscriptfont2}{##2}}%
%\dodosetsubscript{\fontdimen14}{?}%
\dodosetsubscript{\fontdimen16}{.7}%
\dodosetsubscript{\fontdimen17}{.7}%
\global\loweredsubscriptstrue
\endlatexmathmodehack}

\def\resetsubscripts%
{\ifloweredsubscripts
\beginlatexmathmodehack
\def\doresetsubscript##1##2%
{\dimen0=\getvalue{@@\string##1\string##2}\relax
##1##2=\dimen0}%
\def\dodoresetsubscript##1%
{\doresetsubscript{##1}{\textfont2}%
\doresetsubscript{##1}{\scriptfont2}%
\doresetsubscript{##1}{\scriptscriptfont2}}%
%\dodoresetsubscript{\fontdimen14}%
\dodoresetsubscript{\fontdimen16}%
\dodoresetsubscript{\fontdimen17}%
\global\loweredsubscriptsfalse
\endlatexmathmodehack
\fi}

\def\doresetsubscripts%
{\resetsubscripts}

\def\sethighsubscripts%
{\resetsubscripts
\let\dosetsubscripts=\relax}

\def\setlowsubscripts%
{\def\dosetsubscripts{\setsubscripts}}

\setlowsubscripts

\newcount\horchemical % t.z.t. \newcounter
\newcount\verchemical % t.z.t. \newcounter
\newcount\txtchemical % t.z.t. \newcounter
\newcount\levchemical % t.z.t. \newcounter

\newif\ifinchemical \inchemicalfalse
\newif\iffixedchemical \fixedchemicalfalse

\newbox\chemicalsymbols

% Eigenlijk moeten de constanten en variabelen in cont-nl.tex
% staan. Dit pakket is echter relatief onafhankelijk van CONTEXT.

\definesystemvariable {chemical}

\definesystemconstant {chemical}

\definesystemconstant {translate}
\definesystemconstant {distance}
\definesystemconstant {mirror}
\definesystemconstant {rotate}
\definesystemconstant {substitute}
\definesystemconstant {angle}

\definesystemconstant {executechemical}
\definesystemconstant {chemicaltextelement}
\definesystemconstant {chemicallinesegment}
\definesystemconstant {chemicalcircsegment}

\def\chemicalspace {\quad}

% begin van experiment:
%
% De onderstaande twee macro's kunnen worden gebruikt voor
% bijvoorbeeld een interactiemechanisme.
%
% \localgotochemical {verwijzing} {tekst}
% \localthisischemical {verwijzing}

\def\dowithchemical%
{}

\doifdefinedelse{@@iastate}
{\def\localgotochemical#1#2{\naarbox{#2}[#1]}%
\def\localthisischemical#1{\pagereference[#1]}}
{\def\localgotochemical#1{}%
\def\localthisischemical#1{}}

% eind van experiment

\def\setchemicalmaximum #1
{\def\maxchemical{#1}}

\def\doifchemicalnumber#1#2#3%
{\doifnumberelse{#1}
{\ifnum#1>\maxchemical
\writestatus{ppchtex}{number #1 is skipped}%
\else
#3%
\fi}
{\unknownchemical{#2}}}%

\newif\ifsmallchemicaltext

\let\@@localchemicalstyle\empty

\def\setupchemicalformat[#1]%
{\processaction
[\getvalue{#1\c!size}]
[ \v!small=>\def\@@localchemicalformat{\scriptscriptstyle},
\v!medium=>\def\@@localchemicalformat{\ifsmallchemicaltext\scriptscriptstyle\else\scriptstyle\fi},
\v!big=>\def\@@localchemicalformat{\ifsmallchemicaltext\scriptstyle\else\textstyle\fi},
\s!unknown=>\def\@@localchemicalformat{\getvalue{#1\c!size}}]%
\processaction
[\getvalue{#1\c!textsize}]
[ \v!small=>\def\@@localchemicalstyle{\scriptscriptstyle},
\v!medium=>\def\@@localchemicalstyle{\ifsmallchemicaltext\scriptscriptstyle\else\scriptstyle\fi},
\v!big=>\def\@@localchemicalstyle{\ifsmallchemicaltext\scriptstyle\else\textstyle\fi},
\s!unknown=>\def\@@localchemicalstyle{\getvalue{#1\c!textsize}}]%
\processaction
[\getvalue{#1\c!scale}]
[ \v!small=>\def\@@localchemicalscale{500},
\v!medium=>\def\@@localchemicalscale{625},
\v!big=>\def\@@localchemicalscale{750},
\s!unknown=>\def\@@localchemicalscale{\getvalue{#1\c!scale}}]}

\def\@@currentchemicalformat
{\ifinchemical
\@@localchemicalformat
\else
\@@localchemicalstyle
\fi}

\def\dosetupchemical[#1]%
{\getparameters[\??chemical\s!chemical][#1]%
\doifelse{\@@chemicalchemicaloffset}{LOW}
{\setlowsubscripts}
{\sethighsubscripts}%
\setupchemicalformat[\??chemical\s!chemical]%
\ignorespaces}

\def\setupchemical
{\dosingleargument\dosetupchemical}

\def\@@dochemicalstyle% % default mapping
{\@@chemicalstyle}

\def\@@dochemicalcolor% % no mapping yet
{}

\def\@@chemicalstyle % $inner-style$ % (overloaded)
{\@@chemicalchemicalstyle} % $$outer-style$$

\def\@@writechemicalstate#1#2%
{}

\def\@@beginchemicallocalpicture
{\ifcase\chemicaldrawingmode
\beginpicture
\or
\pspicture(0,0)(0,0) % is this permitted ?
\or
\pushMPdrawing
\startMPdrawing
%prologues := 1 ;
%input mp-tool ;
u := 10*\@@chemicalunit;
bboxmargin := 0pt ;
pickup pencircle scaled 2u ; % ???
\stopMPdrawing
\beginpicture
\fi}

\def\@@endchemicallocalpicture#1#2%
{\ifcase\chemicaldrawingmode
\endpicture
\or
\endpspicture
\or
\resetchemicalcoordinates
\setbox2\hbox{\MPshiftdrawingtrue\MPstaticgraphictrue\getMPdrawing}%
\wd2=\!!zeropoint
\ht2=\!!zeropoint
\dp2=\!!zeropoint
\put {\box2} at 0 0
\endpicture
\popMPdrawing
\fi}

\def\@@beginchemicalpicture#1#2#3#4%
{\ifnum\chemicaldrawingmode=1
\pspicture(#1,#3)(#2,#4)%
\def\account##1##2{}%
\psaxes[axesstyle=none,labels=none,ticks=none](#1,#3)(#2,#4)%
\else
\beginpicture
\setplotarea
x from {#1} to {#2},
y from {#3} to {#4}
\iffixedchemical
\accountingon
\def\account##1##2%
{\put {} at {##1} {##2} }%
\else
\accountingoff
\def\account##1##2{}%
\fi
\fi
\ignorespaces}

\def\@@endchemicalpicture%
{\ifcase\chemicaldrawingmode
\put {\box\chemicalsymbols} at 0 0 % elders
\endpicture
\or
\rput(0,0){\box\chemicalsymbols}%
\endpspicture
\or
\put {\box\chemicalsymbols} at 0 0 % elders
\ifMPdrawingdone
\resetchemicalcoordinates
\setbox2\hbox{\MPshiftdrawingtrue\MPstaticgraphictrue\getMPdrawing}%
\wd2=\!!zeropoint
\ht2=\!!zeropoint
\dp2=\!!zeropoint
\put {\box2} at 0 0 %
\fi
\endpicture
\fi}

\def\@@setchemicalcoordinatesystem#1%
{\edef\@@chemicalunit{#1}%
\ifcase\chemicaldrawingmode
\setcoordinatesystem units <\@@chemicalunit,\@@chemicalunit> %
\or
\psset{unit=\@@chemicalunit}%
\or
\setcoordinatesystem units <\@@chemicalunit,\@@chemicalunit> %
\startMPdrawing
%input mp-tool ;
%prologues := 1 ;
u := 10*#1;
bboxmargin := 0pt ;
pickup pencircle scaled 2u ; % ???
\stopMPdrawing
\fi}

\def\@@setchemicalaxis#1#2#3#4%
{\ifcase\chemicaldrawingmode
\axis
bottom shiftedto y=0
ticks from {#1} to {#2} by 500 /
\axis
left shiftedto x=0
ticks from {#3} to {#4} by 500 / %
\or
\psaxes[labels=none,Dx=500,Dy=500](0,0)(#1,#3)(#2,#4)%
\or
\global\MPdrawingdonetrue
\startMPdrawing
x1 := \MPdivten[#1]u ; x2 := \MPdivten[#2]u;
y1 := \MPdivten[#3]u ; y2 := \MPdivten[#4]u;
draw z1--(x2,y1)--z2--(x1,y2)--cycle ;
d := 50u ; dd := 10u ;
draw (x1,0)--(x2,0) ;
draw (0,y1)--(0,y2) ;
for i=d step -d until x1: draw (i,dd)--(i,-dd) ; endfor ;
for i=d step d until x2: draw (i,dd)--(i,-dd) ; endfor ;
for i=d step -d until y1: draw (-dd,i)--(dd,i) ; endfor ;
for i=d step d until y2: draw (-dd,i)--(dd,i) ; endfor ;
\stopMPdrawing
\fi}

\def\@@setsecondchemicalplotsymbol%
{\ifcase\chemicaldrawingmode
\!!widtha=50.8mm
\divide\!!widtha by \@@chemicalresolution\relax
\plotsymbolspacing=\!!widtha
\setplotsymbol({\vrule\!!height\!!widtha\!!width\!!widtha})%
\fi}

% Something for Dirk:

\newcount \currentchemical

%\newif \ifskipchemical

\def\setchemicaldimensions#1#2#3%
{\bgroup
\global\advance\currentchemical by 1
\dimen0=#1\relax
\dimen2=#2\relax
\dimen4=#3\relax
\setxvalue{chemical::\the\currentchemical}%
{\noexpand\docommando{\the\dimen0}{\the\dimen2}{\the\dimen4}}%
\egroup}

%\def\getchemicaldimensions#1#2#3%
% {\global\advance\currentchemical by 1
% \def\docommando##1##2##3%
% {#1=##1\relax#2=##2\relax#3=##3\relax}%
% \doifdefinedelse{chemical::\the\currentchemical}
% {\getvalue{chemical::\the\currentchemical}}
% {\docommando{6cm}{4cm}{0cm}}}
%
%\def\savechemicaldimensions%
% {\bgroup
% \writestatus{ppchtex}{saving dimensions in ppchtex.dim}%
% \def\docommando##1##2##3%
% {\immediate\write\scratchwrite
% {\noexpand\setchemicaldimensions{##1}{##2}{##3}}}%
% \immediate\openout\scratchwrite=ppchtex.dim
% \scratchcounter=0
% \loop
% \ifnum\scratchcounter<\currentchemical
% \advance\scratchcounter by 1
% \getvalue{chemical::\the\scratchcounter}%
% \repeat
% \immediate\closeout\scratchwrite
% \egroup}
%
%\def\loadchemicaldimensions% oh, how nice it would be to use
% {\bgroup % one of the context read commands
% \global\currentchemical=0
% \immediate\openin\scratchread=./ppchtex.dim
% \ifeof\scratchread
% \immediate\closein\scratchread
% \global\skipchemicalfalse
% \else
% \immediate\closein\scratchread
% \input ./ppchtex.dim\relax
% \ifnum\currentchemical>0
% \writestatus{ppchtex}{loading dimensions from ppchtex.dim}%
% \global\skipchemicaltrue
% \else
% \global\skipchemicalfalse
% \fi
% \global\currentchemical=0
% \global\let\savechemicaldimensions=\relax
% \fi
% \egroup
% \global\let\loadchemicaldimensions=\relax}

\ifx\normalchemicalframe\undefined
\let\normalchemicalframe\hbox % hook for educational purposes
\fi

\unexpanded\def\complexstartchemical[#1]%
{\copyparameters
[\??chemical][\??chemical\s!chemical]
[\c!width,\c!height,\c!left,\c!right,\c!top,\c!bottom,
\c!bodyfont,\c!size,\c!scale,\c!state,\c!frame,\c!axis,
\c!location,\c!option,\c!alternative,\c!resolution,\c!offset,\c!style,
\c!color,\c!rulecolor,\c!rulethickness]%
\getparameters
[\??chemical]
[#1]%
%
\setupchemicalformat[\??chemical]%
%
\ifnum\chemicaldrawingmode=2
\resetMPdrawing
\fi
%
\doif{\@@chemicalalternative}{2}
{\@@setsecondchemicalplotsymbol}%
%
\doif{\@@chemicalaxis}\v!on
{\let\chemicalframe\hbox}%
%
\!!counta=250000
\divide\!!counta by \@@localchemicalscale
\!!widtha=\@@chemicalbodyfont
\divide\!!widtha by \!!counta
\@@setchemicalcoordinatesystem{\the\!!widtha}%
%
% \!!counta = -x \!!countc = -y
% \!!countb = +x \!!countd = +y
%
\def\calculateaxis##1##2##3##4##5%
{##1=##3\relax
##2=##4\relax
\ifnum##5=0
\ifnum##3=0
\ifnum##4=0
##1=2000
##2=2000
\fi
\fi
\else
\ifnum##3=0
\ifnum##4=0
##1=##5\relax
\divide##1 by 2
##2=##1\relax
\else
##1=##5\relax
\advance##1 by -##2\relax
\fi
\else
\ifnum##4=0
##2=##5\relax
\advance##2 by -##1\relax
\fi
\fi
\fi}%
\fixedchemicalfalse
\doif\@@chemicalwidth\v!fit
{\edef\@@chemicalwidth
{\ifnum\chemicaldrawingmode=1 2000 \else 1 \fi}%
\fixedchemicaltrue}%
\doif\@@chemicalheight\v!fit
{\edef\@@chemicalheight
{\ifnum\chemicaldrawingmode=1 2000 \else 1 \fi}%
\fixedchemicaltrue}%
\doifelse\@@chemicallocation\v!intext
{\!!counta=0 \!!countb=0
\!!counta=0 \!!countd=0 }
{\calculateaxis
\!!counta\!!countb
\@@chemicalleft\@@chemicalright\@@chemicalwidth
\calculateaxis
\!!countc\!!countd
\@@chemicalbottom\@@chemicaltop\@@chemicalheight}%
%
\edef\@@chemheight {\the\!!countc}%
\edef\@@chemdepth {\the\!!countd}%
\edef\@@chemicaltop{\the\!!countc}%
\edef\@@chemicalbottom{\the\!!countd}%
%
\doifinsetelse\v!on{\@@chemicalframe,\@@chemicalaxis}
{\def\@@chemicalborder{\chemicalframe}}
{\def\@@chemicalborder{\normalchemicalframe}}%
%
\setbox0=\hbox\bgroup % this was a \vbox which took \hsize
%
\@@beginchemicalpicture
{-\the\!!counta}{\the\!!countb}
{-\the\!!countc}{\the\!!countd}%
\doif{\@@chemicalstate}\v!start
{\doif\@@chemicalaxis\v!on
{\@@setchemicalaxis
{-\the\!!counta}{\the\!!countb}
{-\the\!!countc}{\the\!!countd}}}%
\doifelse\@@chemicaloption\v!test
{\def\@@writechemicalstate##1##2%
{\convertargument##2\to\ascii
\writestatus{##1}{\ascii}}}
{\def\@@writechemicalstate##1##2{}}%
\ignorespaces}

\def\dostartchemical%
{\catcode`\^=\@@superscript% t.b.v. \enableduplication
\catcode`\_=\@@subscript % t.b.v. de zekerheid
\begingroup
\inchemicaltrue
\def\toptext##1{\gdef\thetoptext{##1}\ignorespaces}\toptext{}%
\def\bottext##1{\gdef\thebottext{##1}\ignorespaces}\bottext{}%
\def\midtext##1{\gdef\themidtext{##1}\ignorespaces}\midtext{}%
\def\@@chemicalpostponed{}%
\complexorsimpleempty\startchemical}

\def\startchemical%
{\bgroup % t.b.v. ungrouped floats
% \loadchemicaldimensions
% \ifskipchemical
% \def\dostartchemical%
% {\def\dummy[####1]{}\dosingleempty\dummy}%
% \def\chemical%
% {\def\dummy[####1][####2][####3]{}\dotripleempty\dummy}%
% \def\toptext##1{}%
% \def\midtext##1{}%
% \def\bottext##1{}%
% \fi
\dostartchemical}

\def\stopchemical%
{%\ifskipchemical
% \getchemicaldimensions{\dimen0}{\dimen2}{\dimen4}%
% \dimen8=\dimen2\advance\dimen8 by \dimen4
% \setbox0=\vbox to \dimen8
% {\vss\hbox to \dimen0{\hss\the\currentchemical\hss}\vss}%
% \wd0=\dimen0\ht0=\dimen2\dp0=\dimen4
% \chemicalframe{\box0}%
%\else
\checkchemicalpicture
\@@endchemicalpicture
\egroup
\ifnum\chemicaldrawingmode=1
\dimen0=\@@chemicalunit
\setbox0=\hbox{\lower\@@chemdepth\dimen0\box0}%
\ht0=\@@chemheight\dimen0
\dp0=\@@chemdepth\dimen0
\fi
\dimen0=\ht0
\advance\dimen0 by \dp0
\inchemicalfalse % enables \chemie{} in text
\setbox4=\alignedchemical\themidtext
\setbox6=\alignedchemical\thetoptext
\setbox8=\alignedchemical\thebottext
\setbox4=\hbox to \wd0
{\strut\hss$\vcenter{\box4}$\hss}%
\setbox2=\vbox to \dimen0
{\hbox to \wd0{\strut\hss\box6\hss}
\vfill
\hbox to \wd0{\strut\hss\box8\hss}
\vss}% disables the depth
\wd0=0pt \wd4=0pt
\ht2=\ht0 \dp2=\dp0
\ht4=\ht0 \dp4=\dp0
%\setchemicaldimensions{\wd2}{\ht2}{\dp2}%
\@@chemicalborder{\box0\box4\box2}% text on top of chemicals
\endgroup
%\fi
\ignorespaces
\egroup} % t.b.v. ungrouped floats

\def\alignedchemical#1%
{\vtop
{\def\par{\egroup\hbox\bgroup\strut}%
\let\\=\par
\let\endgraf=\par
\hbox\bgroup\strut#1\egroup}}

% \setchemicalcoordinates{#1}{#2}
%
% #1: verplaatsing in x-richting
% #2: verplaatsing in y-richting

\newif\ifchemicaldirection

\def\checkchemicaldirection#1#2%
{\ifchemicaldirection
\ifnum#1>0 \advance\horchemical -\chemicaldirection \fi
\ifnum#1<0 \advance\horchemical +\chemicaldirection \fi
\ifnum#2>0 \advance\verchemical -\chemicaldirection \fi
\ifnum#2<0 \advance\verchemical +\chemicaldirection \fi
\chemicaldirectionfalse
\fi}

\def\processchemicaldirection%
{\chemicaldirectiontrue\processchemicaltranslate}

\def\setchemicalcoordinates#1#2%
{\advance\horchemical #1\relax
\advance\verchemical #2\relax
\checkchemicaldirection{#1}{#2}%
\!!counta=-\horchemical\edef\chemicalxoffset{\the\!!counta}%
\!!countb=-\verchemical\edef\chemicalyoffset{\the\!!countb}%
\ifnum\chemicaldrawingmode=1
% njet
\else
\setcoordinatesystem point at {\the\horchemical} {\the\verchemical}
\fi}

\def\resetchemicalcoordinates%
{\horchemical=0
\verchemical=0
\edef\chemicalxoffset{0}%
\edef\chemicalyoffset{0}%
\ifnum\chemicaldrawingmode=1
% njet
\else
\setcoordinatesystem point at 0 0
\fi}

\def\restorechemicalcoordinates%
{%\writestatus{ppchtex}{restoring \the\horchemical,\the\verchemical}%
\edef\chemicalxoffset{\the\horchemical}%
\edef\chemicalyoffset{\the\verchemical}%
\ifnum\chemicaldrawingmode=1
% njet
\else
\setcoordinatesystem point at {\the\horchemical} {\the\verchemical}
\fi}

\def\setchemicaltranslate #1 #2 #3
{\setvalue{\s!translate#1}{\setchemicalcoordinates{#2}{#3}}}

\def\processchemicaltranslate#1%
{\def\doprocess[##1##2]%
{\doifchemicalnumber{##1}{MOV#1}
{\ifnum##1=0
\def\chemicaloffset{0}% incompatible change
\resetchemicalcoordinates
\else
\getvalue{\s!translate##1}%
\dochemicaloffset{##1}%
\def\chemicaloffset{0}%
\fi}}%
\doprocess[#1]}

\def\setchemicaldistance #1
{\setvalue{\s!distance1}{\setchemicalcoordinates{-#1}{ 0}}%
\setvalue{\s!distance2}{\setchemicalcoordinates{ 0}{ #1}}%
\setvalue{\s!distance3}{\setchemicalcoordinates{ #1}{ 0}}%
\setvalue{\s!distance4}{\setchemicalcoordinates{ 0}{-#1}}}

\def\setchemicaldirection #1
{\def\chemicaldirection{#1}}

\def\processchemicaldistance#1%
{\def\doprocess[##1##2]%
{\doifchemicalnumber{##1}{ADJ#1}
{\ifnum##1=0
\resetchemicalcoordinates
\else
\def\@@chemicalpostponed{\getvalue{\s!distance##1}}%
\@@chemicalpostponed
\fi}}%
\doprocess[#1]}

\def\setchemicalsubstitute #1
{\setvalue{\s!substitute1}{\setchemicalcoordinates{-#1}{ 0}}%
\setvalue{\s!substitute2}{\setchemicalcoordinates{ 0}{ #1}}%
\setvalue{\s!substitute3}{\setchemicalcoordinates{ #1}{ 0}}%
\setvalue{\s!substitute4}{\setchemicalcoordinates{ 0}{-#1}}}

\def\processchemicalsubstitute#1%
{\def\doprocess[##1##2]%
{\doifchemicalnumber{##1}{SUB#1}
{\ifnum##1=0
\resetchemicalcoordinates
\else
\def\@@chemicalpostponed{\getvalue{\s!substitute##1}}%
\@@chemicalpostponed
\fi}}%
\doprocess[#1]}

% Het is mogelijk een offset of move meerdere malen uit te
% voeren, door een nummer voor het commando te plaatsen.

\def\chemicalrepeat {1}

\def\redoprocesschemical[#1#2]%
{\doifinstringelse{#1}{0123456789.}
{\edef\chemicalrepeat{\chemicalrepeat#1}%
\redoprocesschemical[#2]}
{\processchemical[#1#2]%
\def\chemicalrepeat{1}}}

\def\doprocesschemical[#1#2]#3%
{\doifinstringelse{#1}{0123456789.}
{\def\chemicalrepeat{#1}%
\redoprocesschemical[#2]}
{#3}}

% \dochemicaloffset{#1}
%
% #1: binding

\def\chemicaloffset{0}

\def\processchemicaloffset#1%
{\dimen0=62500 sp % real calc on cardinals, funny number
\dimen0=\chemicalrepeat\dimen0
\divide\dimen0 by \@@localchemicalscale
\!!counta=\dimen0
\def\doprocess[##1##2]%
{\doifinstringelse{##1}{128}
{\edef\chemicaloffset{\the\!!counta}}
{\doifinstringelse{##1}{456}
{\edef\chemicaloffset{-\the\!!counta}}
{\doifelse{##1}{0}
{\edef\chemicaloffset{0}}
{\unknownchemical{OFF#1}}}}}%
\doprocess[#1]}

\def\dochemicaloffset#1%
{\ifnum\chemicaloffset=0
\def\undochemicaloffset{}%
\else
\setchemicalcoordinates{-\chemicaloffset}{0}%
\def\undochemicaloffset%
{\setchemicalcoordinates{\chemicaloffset}{0}%
\def\undochemicaloffset{}}%
\fi}

\def\processchemicalphantom#1#2%
{\setbox0=\hbox
{\def\splitoff##1????{##1}%
$\@@dochemicalstyle{\@@localchemicalformat\splitoff#2}$}%
\dimen0=.25\wd0
\divide\dimen0 by \@@localchemicalscale
\!!counta=\dimen0
\doifinstringelse{#1}{128}
{\edef\chemicaloffset{\the\!!counta}}
{\doifinstringelse{#1}{456}
{\edef\chemicaloffset{-\the\!!counta}}
{\doifelse{#1}{0}
{\edef\chemicaloffset{0}}
{\unknownchemical{OF#1:#2}}}}}

% \dosetchemicalrotation{#1}{#2}
%
% #1: cos(phi)
% #2: sin(phi)

\def\chemicalrotation {1}
\def\chemicalangle {0}
\def\chemicalxoffset {0}
\def\chemicalyoffset {0}

\def\setchemicalmirror#1%
{\setvalue{\s!mirror#1}{*}}

\def\resetchemicalmirror#1%
{\resetvalue{\s!mirror#1}}

\def\togglechemicalmirror#1%
{\doifelse{\getvalue{\s!mirror#1}}{*}
{\resetchemicalmirror{#1}}
{\setchemicalmirror{#1}}}

\def\setchemicalrotation #1 #2 #3 #4 #5 #6 #7 #8 #9
{\setvalue{\s!rotate1.#1}{\dosetchemicalrotation{#2}{#3}}%
\setvalue{\s!rotate2.#1}{\dosetchemicalrotation{#4}{#5}}%
\setvalue{\s!rotate3.#1}{\dosetchemicalrotation{#6}{#7}}%
\setvalue{\s!rotate4.#1}{\dosetchemicalrotation{#8}{#9}}}

\def\setchemicalangle #1 #2 #3 #4 #5
{\setvalue{\s!angle1.#1}{\dosetchemicalangle{#2}}%
\setvalue{\s!angle2.#1}{\dosetchemicalangle{#3}}%
\setvalue{\s!angle3.#1}{\dosetchemicalangle{#4}}%
\setvalue{\s!angle4.#1}{\dosetchemicalangle{#5}}}

\def\chemicalrotate[#1]%
{\doifdefinedelse{\s!mirror#1}
{\getvalue{\s!rotate\chemicalrotation.#1\getvalue{\s!mirror#1}}%
\getvalue{\s!angle\chemicalrotation.#1\getvalue{\s!mirror#1}}}
{\getvalue{\s!rotate\chemicalrotation.#1}%
\getvalue{\s!angle\chemicalrotation.#1}}}

\def\dosetchemicalangle#1% zwak zie onder
{\def\chemicalangle{#1}}

\def\dosetchemicalrotation#1#2%
{\ifnum\chemicaldrawingmode=1
% njet
\else
\startrotation by {#1} {#2} %% \stoprotation (t.b.v. testen)
\fi}

\def\doresetchemicalrotation
{\ifnum\chemicaldrawingmode=1
% njet
\else
\stoprotation
\fi}

\def\processchemicalrotation#1%
{\def\doprocess[##1##2]%
{\doifnumberelse{##1}
{\def\chemicalrotation{##1}}
{\unknownchemical{ROT#1}}}%
\doprocess[#1]}

% \filtertextelement[#1][#2][#3][#4]
%
% #1: volgnummer
% #2: offset in uitlijningen
% #3: lijst met uitlijningen -> \chemicalloca
% #4: lijst met teksten -> \chemicaltext

\def\setchemicallocation#1%
{\doifelse{#1}{}
{\edef\chemicalloca{c}}
{\edef\chemicalloca{#1}}}

\newif\iffixedchemicaltext

\def\filterchemicaltextelement[#1][#2][#3][#4]%
{\ifchemicaltextconstant
\def\chemicaltext{#4}%
\setchemicallocation{}%
\else
\ifnum#1=0\relax
\setchemicallocation{}%
\else
\iffixedchemicaltext
\!!counta#2
\else
\!!counta=\chemicalrotation
\advance\!!counta -1
\multiply\!!counta #2
\advance\!!counta #1
\fi
\getfromcommalist[#3][\the\!!counta]%
\setchemicallocation\commalistelement
\fi
\ifchemicalpicture
\let\chemicaltext\relax
\else
\advance\txtchemical 1
\getfromcommalist[#4][\txtchemical]%
\let\chemicaltext\commalistelement
\fi
\fi
\fixedchemicaltextfalse}

% \putchemicaltext{#1}{#2}
%
% #1 : x-coordinaat
% #2 : y-coordinaat
%
% \chemicaltext en \chemicalloca worden met \gettextelement
% opgehaald uit de tweede set bij \chemie
%
% Ten behoeve van testdoeleinden wordt gebruik gemaakt van
% \chemicalframe in plaats van het meer sjieke, maar tevens
% meer trage \framed.

\ifx\ruledhbox\undefined
\def\chemicalframe#1%
{\hbox
{\vrule\hskip-.4pt
\vbox{\hrule\vskip-.4pt\hbox{#1}\vskip-.4pt\hrule}%
\hskip-.4pt\vrule}}
\else
\def\chemicalframe#1%
{\ruledhbox{#1}}
\fi

\def\doputchemicaltext#1 [#2] at #3 #4 %
{\ifnum\chemicaldrawingmode=1
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\expanded{\rput[#2]{\chemicalangle}(#3,#4){#1}}}%
\else
\put {#1} [#2] at {#3} {#4} %
\fi}

\def\dodoifsinglelocation#1#2\\#3%
{\ifx#2\relax#3\fi}

\def\doifsinglelocationelse#1%
{\expandafter\dodoifsinglelocationelse#1\relax\\}

\def\putchemicaltext#1#2%
{\enablechemicalspecials
\ifchemicalpicture
\setchemicalpicture{#1}{#2}%
\else
\doifelse\@@chemicaloption\v!test
{\def\@@chemicalframe{\chemicalframe}}
{\def\@@chemicalframe{}}%
\dosetsubscripts
\setbox2=\hbox{$\@@dochemicalstyle{\@@localchemicalformat \chemicaltext}$}%
\setbox4=\hbox{$\@@dochemicalstyle{\@@localchemicalformat C_2^2}$}%
\setbox6=\hbox{$\@@dochemicalstyle{\@@localchemicalformat O}$}% or C
\doresetsubscripts
\doifnot\@@chemicallocation\v!intext
{\ht2=\ht4
\dp2=\dp4}%
\setbox2=\hbox{\@@chemicalframe{\@@dochemicalcolor\box2}}%
\ifdim\wd2>\wd6
\doifelse{#1}{0}
{\doifnot{#2}{0}{\wd2=\wd6}}
{%\doifsinglelocation\chemicalloca
{\doifinset{\chemicalloca}{t,b}{\wd2=\wd6}}}% common ?
\fi
\expanded
{\doputchemicaltext
{\noexpand\dowithchemical{\copy2}} % per se \copy2 i.p.v. \box2
[\chemicalloca] at {#1} {#2} }
\nomoreaccounting
\fi
\disablechemicalspecials}

\def\setchemicaltextelement #1 #2 #3
{\setvalue{\s!chemicaltextelement#1}{\putchemicaltext{#2}{#3}}}

\def\getchemicalfixedtextelement%
{\fixedchemicaltexttrue
\getchemicaltextelement}

\def\getchemicaltextelement[#1][#2][#3][#4][#5]%
{\filterchemicaltextelement[#2][#3][#4][#5]%
\doifelse{#2}{0}
{\dochemicaloffset{#2}% % incompatible change
\putchemicaltext{0}{0}%
\undochemicaloffset} % incompatible change
{\chemicalrotate[#2]%
\dochemicaloffset{#2}%
\def\chemicaltextelementnumber{#2}%
\getvalue{\s!chemicaltextelement#1}%
\getvalue{\s!chemicaltextelement#11}%
\getvalue{\s!chemicaltextelement#12}%
\getvalue{\s!chemicaltextelement#13}%
\undochemicaloffset}}

\def\processchemicaltextelement#1#2#3#4#5%
{\def\doprocess[##1##2##3##4##5]%
{\doifelse{##1}{?}
{\doprocess[1..\maxchemical ????]}
{\doifchemicalnumber{##1}{#1#2}
{\doifelse{##2##3}{..}
{\doifchemicalnumber{##4}{#1#2}
{\getchemicaltextelement[#1][##1][#4][#5][#3]%
\doifnot{##1}{##4}
{\!!counta=##1\relax
\advance\!!counta by 1
\edef\nextsegment{\the\!!counta}%
\doprocess[\nextsegment..##4##5]}}}
{\getchemicaltextelement[#1][##1][#4][#5][#3]%
\doifnot{##2}{?}{\doprocess[##2##3##4##5]}}}}}%
\doprocess[#2]%
\smallchemicaltextfalse}

\def\processchemicalsmalltextelement%
{\smallchemicaltexttrue\processchemicaltextelement}

\def\processchemicalsmalltextconstant%
{\smallchemicaltexttrue\processchemicaltextconstant}

\def\processchemicalunrotatedtextelement#1#2#3#4#5#6%
{\bgroup
\xdef\@@xxx{0}%
\xdef\@@yyy{0}%
\def\putchemicaltext##1##2%
{\xdef\@@xxx{##1}%
\xdef\@@yyy{##2}}%
\getvalue{\s!chemicaltextelement#1}%
\egroup
\bgroup
\def\doputchemicaltext##1 [##2] at ##3 ##4 %
{\ifnum\chemicaldrawingmode=1
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\rput{\chemicalangle}(\@@xxx,\@@yyy){\expanded{\rput[##2](##3,##4){##1}}}}%
\else
\put
{\stoprotation \setcoordinatesystem point at 0 0
\expanded{\put {##1} [##2] at {##3} {##4} }}
at {\@@xxx} {\@@yyy}
\fi}%
\processchemicaltextelement{#2}{#3}{#4}{#5}{#6}%
\egroup}

\newif\ifchemicaltextconstant

\def\processchemicaltextconstant#1#2#3#4%
{\chemicaltextconstanttrue
\let\@@oldchemicalframe\@@chemicalframe
\let\@@chemicalframe\relax
\processchemicaltextelement{#1}{#2}{#3}{#4}{}%
\let\@@chemicalframe\@@oldchemicalframe
\chemicaltextconstantfalse}

% \plotchemicalline{#1}{#2}{#3}{#4}
%
% #1: x-coordinaat beginpunt
% #2: y-coordinaat beginpunt
% #3: x-coordinaat eindpunt
% #4: y-coordinaat eindpunt

\chardef\chemicallinetype=0

\def\doplotchemicalline%
{\!!counte=\!!countc \advance\!!counte by -\!!counta
\!!countf=\!!countd \advance\!!countf by -\!!countb
\bgroup
\ifcase\chemicaldrawingmode
\ifcase\chemicallinetype
% 0 : normal line
\plot {\!!counta} {\!!countb} {\!!countc} {\!!countd} /%
\or
% 1 : normal arrow
\arrow <5pt> [.2,.67] from {\!!counta} {\!!countb} to {\!!countc} {\!!countd}
\or
% 2 : reverse arrow
\arrow <5pt> [.2,.67] from {\!!countc} {\!!countd} to {\!!counta} {\!!countb}
\or
% 3 : unrotated line
\put {\stoprotation \setcoordinatesystem point at 0 0
\plot 0 0 {\!!counte} {\!!countf} /}
[\chemicallineposition] at {\!!counta} {\!!countb}
\else
% 4 : dashed line
\findlength {\plot {\!!counta} {\!!countb} {\!!countc} {\!!countd} /}%
\setdashesnear <2pt> for <\totalarclength>%
\plot {\!!counta} {\!!countb} {\!!countc} {\!!countd} /%
\fi
\or
\ifcase\chemicallinetype
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psline(\!!counta,\!!countb)(\!!countc,\!!countd)}%
\or
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psline{->}(\!!counta,\!!countb)(\!!countc,\!!countd)}%
\or
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psline{<-}(\!!counta,\!!countb)(\!!countc,\!!countd)}%
\or
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\expanded{\rput[\chemicallineposition]{-\chemicalangle}%
(\!!counta,\!!countb){\psline(0,0)(\!!counte,\!!countf)}}}%
\else
\psset{linestyle=dashed}%
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psline(\!!counta,\!!countb)(\!!countc,\!!countd)}%
\fi
\or
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
x0 := \MPdivten[\chemicalxoffset]u ;
y0 := \MPdivten[\chemicalyoffset]u ;
x1 := \MPdivten[\the\!!counta]u ;
y1 := \MPdivten[\the\!!countb]u ;
x2 := \MPdivten[\the\!!countc]u ;
y2 := \MPdivten[\the\!!countd]u ;
x3 := \MPdivten[\the\!!counte]u ;
y3 := \MPdivten[\the\!!countf]u ;
\ifcase\chemicallinetype
% 0 : normal line
draw ((z1--z2) rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\or
% 1 : normal arrow
drawarrow ((z1--z2) rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\or
% 2 : reverse arrow
drawarrow ((z2--z1) rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\or
% 3 : unrotated line % nog \chemicalineposition: t/b
draw (origin--z3)
shifted (z1 rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\else
% 4 : dashed line
draw ((z1--z2) rotatedaround(origin,-\chemicalangle))
% shifted z0 dashed evenly ;
shifted z0 dashed dashpattern(on 5.5u off 6u) ;
\fi
\stopMPdrawing
\fi
\egroup
\account\!!counta\!!countb
\account\!!countc\!!countd}

\def\plotchemicalline#1#2#3#4%
{\!!counta=#1\!!countb=#2\!!countc=#3\!!countd=#4\relax
\doplotchemicalline}

\def\plotchemicalzline#1#2#3#4%
{\!!counta=#1\!!countb=#2\!!countc=#3\!!countd=#4\relax
\ifnum\chemicaldrawingmode=2
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
x0 := \MPdivten[\chemicalxoffset]u ;
y0 := \MPdivten[\chemicalyoffset]u ;
x1 := \MPdivten[\the\!!counta]u ;
y1 := \MPdivten[\the\!!countb]u ;
x2 := \MPdivten[\the\!!countc]u ;
y2 := \MPdivten[\the\!!countd]u ;
filldraw ((
\ifnum\chemicalangle>180
z1--z2
\else\ifnum\chemicalangle<90
z1--(z2 shifted (-2u,+2u))--(z2 shifted (+2u,-2u))
\else\ifnum\chemicalangle=90
(z1 shifted (-2u,+2u))--(z1 shifted (+2u,-2u))--
(z2 shifted (+2u,+2u))--(z2 shifted (-2u,-2u))
\else
(z1 shifted (+2u,+2u))--(z1 shifted (-2u,-2u))--z2
\fi\fi\fi
--cycle) rotatedaround(origin,-\chemicalangle)) shifted z0 ;
\stopMPdrawing
\else
\doplotchemicalline
\ifnum\chemicalangle>180 \else
\ifnum\chemicalangle=90
\advance\!!counta by -20 \advance\!!countc by -20
\doplotchemicalline
\advance\!!counta by 40 \advance\!!countc by 40
\else\ifnum\chemicalangle<90
\advance\!!countc by -20 \advance\!!countd by +20
\doplotchemicalline
\advance\!!countc by +40 \advance\!!countd by -40
\else
\advance\!!counta by 20 \advance\!!countb by 20
\doplotchemicalline
\advance\!!counta by -40 \advance\!!countb by -40
\fi\fi
\fi
\doplotchemicalline
\fi}

\def\plotchemicaldeltaline#1#2#3#4%
{\!!counta=#1\!!countb=#2\!!countc=#3\!!countd=#4\relax
\ifnum\chemicaldrawingmode=2
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
x0 := \MPdivten[\chemicalxoffset]u ;
y0 := \MPdivten[\chemicalyoffset]u ;
x1 := \MPdivten[\the\!!counta]u ;
y1 := \MPdivten[\the\!!countb]u ;
x2 := \MPdivten[\the\!!countc]u ;
y2 := \MPdivten[\the\!!countd]u ;
filldraw ((z1--(z2 rotatedaround(z1,5))--(z2 rotatedaround(z1,-5))
--cycle) rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\stopMPdrawing
\account{#1}{#2}%
\account{#3}{#4}%
\else
\doplotchemicalline
\advance\!!countc by 16 \advance\!!countd by -21
\doplotchemicalline
\advance\!!countc by -4 \advance\!!countd by 7
\doplotchemicalline
\advance\!!countc by -4 \advance\!!countd by 7
\doplotchemicalline
\advance\!!countc by -8 \advance\!!countd by 14
\doplotchemicalline
\advance\!!countc by -4 \advance\!!countd by 7
\doplotchemicalline
\advance\!!countc by -4 \advance\!!countd by 7
\doplotchemicalline
\advance\!!countc by -4 \advance\!!countd by 7
\doplotchemicalline
\fi}

\def\setchemicallinesegment #1 #2 #3 #4 #5
{\setvalue{\s!chemicallinesegment#1}{\plotchemicalline{#2}{#3}{#4}{#5}}}

\def\getchemicallinesegment[#1][#2]%
{\chemicalrotate[#1]%
\dochemicaloffset{#1}%
\getvalue{\s!chemicallinesegment#2}%
\getvalue{\s!chemicallinesegment#21}%
\getvalue{\s!chemicallinesegment#22}%
\undochemicaloffset}

\def\getprivatechemicallinesegment[#1][#2]%
{\chemicalrotate[#1]%
\getvalue{\s!chemicallinesegment#2#1}}

\def\doprocesschemicallinesegment#1#2#3#4#5%
{\chardef\chemicallinetype=#1
\def\chemicallineposition{#2}%
\def\doprocess[##1##2##3##4##5]%
{\doifelse{##1}{?}
{\doprocess[1..\maxchemical ????]}
{\doifchemicalnumber{##1}{#4#5}
{\doifelse{##2##3}{..}
{\doifchemicalnumber{##4}{#4#5}
{#3[##1][#4]%
\doifnot{##1}{##4}
{\!!counta=##1\relax
\advance\!!counta by 1
\edef\nextsegment{\the\!!counta}%
\doprocess[\nextsegment..##4##5]}}}
{#3[##1][#4]%
\doifnot{##2}{?}
{\doprocess[##2##3##4##5]}}}}}%
\doprocess[#5]}

\def\processchemicallinesegment%
{\doprocesschemicallinesegment0c\getchemicallinesegment}

\def\processchemicalzlinesegment#1#2%
{%\doprocesschemicallinesegment0c\getchemicallinesegment{#1}{#2}%
\bgroup
\def\plotchemicalline{\plotchemicalzline}%
\doprocesschemicallinesegment0c\getchemicallinesegment{#1}{#2}%
\egroup}

\def\processchemicaldeltalinesegment#1#2%
{%\doprocesschemicallinesegment0c\getchemicallinesegment{#1}{#2}%
\bgroup
\def\plotchemicalline{\plotchemicaldeltaline}%
\doprocesschemicallinesegment0c\getchemicallinesegment{#1}{#2}%
\egroup}

\def\processprivatechemicallinesegment%
{\doprocesschemicallinesegment0c\getprivatechemicallinesegment}

\def\processchemicaldownarrowsegment%
{\doprocesschemicallinesegment1c\getchemicallinesegment}

\def\processchemicaluparrowsegment%
{\doprocesschemicallinesegment2c\getchemicallinesegment}

\def\processchemicalunrotatedlinesegment#1%
{\doprocesschemicallinesegment3{#1}\getchemicallinesegment}

\def\processchemicaldashedlinesegment%
{\doprocesschemicallinesegment4c\getchemicallinesegment}

\def\processchemicalopenend#1#2%
{\doprocesschemicallinesegment0c\doprocesschemicalopenend{#1}{#2}}

\def\doprocesschemicalopenend[#1][#2]%
{\chemicalrotate[#1]%
\dochemicaloffset{#1}%
\ifcase\chemicaldrawingmode
\beginpicture
\setquadratic\plot
300 0 400 0
500 0 550 75
600 0 650 -75
700 0 750 75
800 0 850 -75
900 0 950 0
1050 0 /
\endpicture
\or
\rput{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psline(300,0)(500,0)%
\rput(500,0){\psplot[yunit=75,plotstyle=curve]{0}{720}{x sin}}%
\psline(950,0)(1050,0)}%
\or
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
x0 := \MPdivten[\chemicalxoffset]u ;
y0 := \MPdivten[\chemicalyoffset]u ;
draw
(((30.0u,0)--(50.0u,0){up}..(55.0u,7.5u)..
(60.0u,0)..(65.0u,-7.5u)..(70.0u,0)..
(75.0u,7.5u)..(80.0u,0)..(85.0u,-7.5u)..{up}
(90.0u,0)--(105.0u,0)) rotatedaround(origin,-\chemicalangle))
shifted z0 ;
\stopMPdrawing
\fi
\undochemicaloffset}

% \plotchemicalcircle{#1}{#2}{#3}{#4}
%
% #1: lengte van de boog in graden
% #2: x-coordinaat eindpunt
% #3: y-coordinaat eindpunt

\newif\ifchemicaldotted

\def\plotchemicalcircle#1#2#3#4#5#6%
{\bgroup
\ifcase\chemicaldrawingmode
\ifchemicaldotted
\findlength{\circulararc {#4} degrees from {#5} {#6} center at {0} {0} }%
\divide\totalarclength by 6
\def\b{\the\totalarclength}%
\divide\totalarclength by 2
\def\a{\the\totalarclength}%
\setdashpattern <\a,\b,\b,\b,\b,\b,\a>
\fi
\circulararc {#4} degrees from {#5} {#6} center at {0} {0} %
\or
\ifchemicaldotted
\psset{linestyle=dashed}%
\fi
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\psarc(0,0){#3}{#1}{#2}}%
\or
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
r := \MPdivten[#3]*2u;
x0 := \MPdivten[\chemicalxoffset]u ;
y0 := \MPdivten[\chemicalyoffset]u ;
draw ((subpath (#1/45,#2/45) of (fullcircle scaled (r)))
rotatedaround (origin,\chemicalangle+150))
shifted z0 \ifchemicaldotted dashed withdots \fi ;
\stopMPdrawing
\fi
\egroup}

\def\setchemicalcircsegment #1 #2 #3 #4 #5 #6 #7
{\setvalue{\s!chemicalcircsegment#1}{\plotchemicalcircle{#2}{#3}{#4}{#5}{#6}{#7}}}

\def\getchemicalcircsegment[#1][#2]%
{\chemicalrotate[#1]%
\getvalue{\s!chemicalcircsegment#2}}

\def\doprocesschemicalcircsegment#1#2%
{\def\doprocess[##1##2##3##4##5]%
{\doifelse{##1}{?}
{\doprocess[1..\maxchemical ????]}
{\doifchemicalnumber{##1}{#1#2}
{\doifelse{##2##3}{..}
{\doifchemicalnumber{##4}{#1#2}
{\getchemicalcircsegment[##1][#1]%
\doifnot{##1}{##4}
{\!!counta=##1\relax
\advance\!!counta by 1
\edef\nextsegment{\the\!!counta}%
\doprocess[\nextsegment..##4##5]}}}
{\getchemicalcircsegment[##1][#1]%
\doifnot{##2}{?}
{\doprocess[##2##3##4##5]}}}}}%
\doprocess[#2]}

\def\processchemicalcircsegment%
{\chemicaldottedfalse\doprocesschemicalcircsegment}

\def\processchemicaldottsegment%
{\chemicaldottedtrue\doprocesschemicalcircsegment}

\let\endchemicalpicture = \relax
\let\checkchemicalpicture = \relax
\let\nomoreaccounting = \relax

\newif\ifchemicalpicture

\def\beginchemicalpicture#1% NO PSTRICKS SUPPORT YET
{\checkchemicalpicture
\bgroup % DOES NOT HANDLE AUTOWIDTH/HEIGHT
\chemicalpicturetrue
\processchemical[#1]}

\def\setchemicalpicture#1#2%
{\chemicalpicturefalse
\def\endchemicalpicture%
{\@@endchemicallocalpicture{#1}{#2}%
\egroup
\ifnum\chemicaldrawingmode=1
\rput
{-\chemicalangle}(\chemicalxoffset,\chemicalyoffset)%
{\expanded{\rput[\chemicalloca]{\chemicalangle}(#1,#2){\box\nextbox}}}%
\else
\expanded{\put{\box\nextbox}[\chemicalloca] at {#1} {#2} }
\fi
\egroup}%
\def\checkchemicalpicture%
{\ifx\endchemicalpicture\relax \else
\writestatus{ppchtex}{missing end of picture (PE)}%
\endchemicalpicture
\fi}%
\setbox\nextbox=\hbox\bgroup
\@@beginchemicallocalpicture
% alternatief: gewoon accounting, en zelf l,r afhandelen
\ifnum\chemicaldrawingmode=1
% njet
\else
\accountingon
\let\nomoreaccounting=\accountingoff
\fi}

\def\doskipchemical[#1][#2]%
{{\tt[ppchtex]}}

\def\skipchemical%
{\dodoubleargument\doskipchemical}

\def\complexchemical% met \expandafter
{\ifinchemical
\expandafter\dochemical
\else
\writestatus{ppchtex}{the [][]-alternative is not permitted here}%
\expandafter\skipchemical
\fi}

\newif\ifinnerchemical

\def\dosimplechemical#1#2#3%
{\doifdefinedelse{\??chemical\c!location}
{\writestatus{ppchtex}{the {}{}-alternative is not permitted here}}
{\ifinnerchemical
\let\chemicalsign = \chemicalinnersign
\let\chemicalmolecule = \chemicalinnermolecule
\let\chemicalsinglearrow = \chemicalsingleinnerarrow
\let\chemicaldoublearrow = \chemicaldoubleinnerarrow
\let\chemicaltwintiparrow = \chemicaltwintipinnerarrow
\else
\let\chemicalsign = \chemicaloutersign
\let\chemicalmolecule = \chemicaloutermolecule
\let\chemicalsinglearrow = \chemicalsingleouterarrow
\let\chemicaldoublearrow = \chemicaldoubleouterarrow
\let\chemicaltwintiparrow = \chemicaltwintipouterarrow
\fi
\disablechemicalspecials
\unexpandedprocessallactionsinset
[#1]
[ HIGH=>\sethighsubscripts,
LOW=>\setlowsubscripts,
PLUS=>\chemicalsign{+},
GIVES=>\chemicalsinglearrow{#2}{#3},
EQUILIBRIUM=>\chemicaldoublearrow{#2}{#3},
MESOMERIC=>\chemicaltwintiparrow{#2}{#3},
SINGLE=>\singlechemicalbond,
DOUBLE=>\doublechemicalbond,
TRIPLE=>\triplechemicalbond,
+=>\chemicalsign{+},
->=>\chemicalsinglearrow{#2}{#3},
<->=>\chemicaldoublearrow{#2}{#3},
<>=>\chemicaltwintiparrow{#2}{#3},
-=>\singlechemicalbond,
--=>\doublechemicalbond,
---=>\triplechemicalbond,
\s!unknown=>\enablechemicalspecials
\chemicalmolecule{\commalistelement}{#2}{#3}]}}

%\def\dosimplechemicalA#1#2#3%
% {\let\chemicalspace=\relax
% \def\dodosimplechemical##1%
% {\dosimplechemical{##1}{}{}}%
% \@EA\processcommalist\@EA[\@@chemicalchemicaloffset,#1]\dodosimplechemical
% \egroup}

\def\dosimplechemicalA#1#2#3% % evt: {#1,\relax}
{\let\chemicalspace=\relax
\@EA\dosimplechemical\@EA{\@@chemicalchemicaloffset,#1}{#2}{#3}%
\egroup}

\def\dosimplechemicalB#1#2#3%
{\dosimplechemical{#1}{#2}{#3}%
\egroup}

\def\dosimplechemicalC#1#2#3%
{$\simplechemical{#1}{#2}{#3}$%
\egroup} % erbij

\def\simplechemical%
{\ifinner
\innerchemicaltrue
\else
\innerchemicalfalse
\fi
\bgroup
\catcode`\^=\@@superscript % t.b.v. \enableduplication
\catcode`\_=\@@subscript % t.b.v. de zekerheid
\ifmmode
\ifinnerchemical
\def\next{\dotriplegroupempty\dosimplechemicalA}%
\else
\def\next{\dotriplegroupempty\dosimplechemicalB}%
\fi
\else
\def\next{\dotriplegroupempty\dosimplechemicalC}%
\fi
\next}

\definecomplexorsimple\chemical

\def\dogotochemical#1#2%
{\def\dowithchemical% % experiment
{\localgotochemical{#1}}% % experiment
\chemical} % experiment

\def\gotochemical% % experiment
{\dosingleargument\dogotochemical} % experiment

\def\dododochemical#1[#2][#3]% % experiment
{\def\simpledododochemical% % experiment
{#1[#2][#3]}% % experiment
\def\complexdododochemical[##1]% % experiment
{\def\dowithchemical% % experiment
{\localthisischemical{#2}}% % experiment
#1[#3][##1]}% % experiment
\complexorsimple\dododochemical} % experiment

\def\dodochemical[#1][#2]%
{\ignorespaces
\ifinchemical
\drawchemical[#1][#2]%
\ignorespaces
\else
\startchemical[\c!location=\v!intext]%
\drawchemical[#1][#2]%
\expandafter\stopchemical
\fi
\ignorespaces}

\def\dochemical[#1]%
{\def\simpledochemical%
{\@@writechemicalstate{ppchtex}{[#1][]}%
\dodochemical[#1][]}%
%
\def\complexdochemical[##1]%
{\@@writechemicalstate{ppchtex}{[#1][##1]}%
\txtchemical=0%
\dodochemical[#1][##1]}%
%
\def\complexdochemical[##1]% % experiment
{\@@writechemicalstate{ppchtex}{[#1][##1]}% % experiment
\txtchemical=0% % experiment
\dododochemical\dodochemical[#1][##1]}% % experiment
%
\complexorsimple\dochemical}

% \processlocalchemicals{#1}
%
% #1: commando's

\def\dodoprocesschemical#1%
{\processchemical[#1????]}

\def\processlocalchemicals#1%
{\processcommalist[#1]\dodoprocesschemical}

% \drawchemical[#1][#2]
%
% #1: bindingen enz.
% #2: atomen enz.

\def\localdodochemical[#1][#2]%
{\@@writechemicalstate{ppchtex}{[#1][#2]}%
%\bgroup % koppelen en afmetingen gaat fout, vandaar:
\advance\levchemical 1
\letvalue{\??chemical\s!unknown\the\levchemical}\unknownchemical
\setevalue{\??chemical\c!text\the\levchemical}{\the\txtchemical}%
\txtchemical=0
\dodochemical[#1][#2]%
% \@EA\txtchemical\@EA\csname\??chemical\c!text\the\levchemical\endcsname
\txtchemical\csname\??chemical\c!text\the\levchemical\endcsname
\@EA\let\@EA\unknownchemical\csname\??chemical\s!unknown\the\levchemical\endcsname
\advance\levchemical -1
%\egroup
\ignorespaces}

\def\drawchemical[#1][#2]%
{\ignorespaces
\def\dodochemical[##1][##2]%
{\drawchemical[##1][##2]%
\ignorespaces}%
\def\dochemical[##1]%
{\def\simpledochemical%
{\@@writechemicalstate{ppchtex}{[##1][#2]}%
\dodochemical[##1][#2]%
\ignorespaces}%
\def\complexdochemical[####1]%
{\dododochemical\localdodochemical[##1][####1,#2]}%
\complexorsimple\dochemical}%
\doif\@@chemicalstate\v!start
{\doifelse\chemicalname\s!unknown
{\getvalue{\s!executechemical\defaultchemical}[#2]}
{\getvalue{\s!executechemical\chemicalname}[#2]}%
\def\unknownchemical##1%
{\processunknownchemical[##1][#2]}%
\processcommalist[\@@chemicaloffset,#1]\dodoprocesschemical}%
\ignorespaces}

\def\chemicaloxidation#1#2#3%
{\chemicaltop
{\ifnum#20=0
0%
\else
#1\expandafter\uppercase\expandafter{\romannumeral#2}%
\fi}
{#3}}

\def\chemicaltfraction{\ifinchemical.60\else.8\fi}
\def\chemicalbfraction{\ifinchemical.45\else.6\fi}
\def\chemicallfraction{\ifinchemical.1\else.1\fi}
\def\chemicalrfraction{\ifinchemical.1\else.1\fi}

\def\chemicaltighttext%
{\def\chemicaltfraction{\ifinchemical.3\else.6\fi}%
\def\chemicalbfraction{\ifinchemical.2\else.4\fi}%
\def\chemicallfraction{\ifinchemical0\else0\fi}%
\def\chemicalrfraction{\ifinchemical0\else0\fi}}

\def\dochemicaltop#1#2#3#4%
{\vbox
{\@@dochemicalcolor
\baselineskip=\chemicaltfraction\baselineskip \lineskip0pt
\halign
{#1###2\cr
$\@@dochemicalstyle{\scriptscriptstyle#3}$\cr
$\@@dochemicalstyle{\@@currentchemicalformat#4}$\cr}}}

\def\dochemicalbottom#1#2#3#4%
{\vtop
{\@@dochemicalcolor
\baselineskip=\chemicalbfraction\baselineskip \lineskip0pt
\halign
{#1###2\cr
$\@@dochemicalstyle{\@@currentchemicalformat#4}$\cr
$\@@dochemicalstyle{\scriptscriptstyle#3}$\cr}}}

\def\chemicalleft#1#2%
{\hbox
{\@@dochemicalcolor
$\@@dochemicalstyle{\scriptscriptstyle#1}$%
$\@@dochemicalstyle{\@@currentchemicalformat\hskip\chemicallfraction em#2}$}}

\def\chemicalright#1#2%
{\hbox
{\@@dochemicalcolor
$\@@dochemicalstyle{\@@currentchemicalformat#2\hskip\chemicalrfraction em}$%
$\@@dochemicalstyle{\scriptscriptstyle#1}$}}

\def\chemicalcentered#1%
{\setbox0=\hbox{$\@@dochemicalstyle{\scriptscriptstyle#1}$}%
\setbox2=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat C}$}%
\dimen0=.5\ht2
\advance\dimen0 by -.5\ht0
\advance\dimen0 by \dp0
\hbox{\@@dochemicalcolor\raise\dimen0\box0}}

\def\chemicalleftcentered#1#2%
{\hbox
{\@@dochemicalcolor
\chemicalcentered{#1}%
$\@@dochemicalstyle{\@@currentchemicalformat\hskip\chemicallfraction em#2}$}}

\def\chemicalrightcentered#1#2%
{\hbox
{\@@dochemicalcolor
$\@@dochemicalstyle{\@@currentchemicalformat#2\hskip\chemicalrfraction em}$%
\chemicalcentered{#1}}}

\def\chemicaltop {\dochemicaltop \hss \hss }
\def\chemicallefttop {\dochemicaltop \relax \hss }
\def\chemicalrighttop {\dochemicaltop \hss \relax}
\def\chemicalbottom {\dochemicalbottom \hss \hss }
\def\chemicalleftbottom {\dochemicalbottom \relax \hss }
\def\chemicalrightbottom {\dochemicalbottom \hss \relax}

\def\chemicaltopleft #1{\chemicalleft {\chemicallefttop {#1}{}}}
\def\chemicalbottomleft #1{\chemicalleft {\chemicalleftbottom{#1}{}}}
\def\chemicaltopright #1{\chemicalright{\chemicallefttop {#1}{}}}
\def\chemicalbottomright#1{\chemicalright{\chemicalleftbottom{#1}{}}}

\def\chemicalsmashedleft#1%
{\hbox\bgroup
\@@dochemicalcolor
\setbox0=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat C}$}%
\setbox2=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat#1}$}%
\wd2=\wd0
\box2
\egroup}

\def\chemicalsmashedmiddle#1%
{\hbox\bgroup
\@@dochemicalcolor
\setbox0=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat C}$}%
\setbox2=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat#1}$}%
\hbox{\hskip-.5\wd2\hskip.5\wd0\box2}
\egroup}

\def\chemicalsmashedright#1%
{\hbox\bgroup
\@@dochemicalcolor
\setbox0=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat C}$}%
\setbox2=\hbox{$\@@dochemicalstyle{\@@currentchemicalformat#1}$}%
\hbox to \wd0{\hskip-\wd2\hskip\wd0\box2}%
\egroup}

\def\+{\tabalign} % is \long in Plain

\def\chemicalforever#1#2%
{\bgroup
\setbox0=\hbox
{\@@dochemicalcolor
$\@@dochemicalstyle{\scriptscriptstyle\hskip-.15em#2}$}%
\wd0=0pt
\big#1_{\hskip.1em\box0}%
\egroup}

\def\disablechemicalspecials%
{\def\+##1{##1}\def\-##1{##1}%
\def\[{[}\def\]{]}%
\def\1{}\def\2{}\def\3{}\def\4{}\def\5{}\def\6{}\def\7{}%
\def\X{}%
\def\T{}\def\B{}\def\L{}\def\R{}\def\LC{}\def\RC{}%
\def\TL{}\def\BL{}\def\TR{}\def\BR{}%
\def\LT{}\def\LB{}\def\RT{}\def\RB{}%
\def\SL{}\def\SM{}\def\SR{}}

\def\enablechemicalspecials%
{\def\+{\dodoublegroupempty\chemicaloxidation{+}}% {} needed!
\def\-{\dodoublegroupempty\chemicaloxidation{-}}% {} needed!
\def\[{\dodoublegroupempty\chemicalforever {[}}% {} needed!
\def\]{\dodoublegroupempty\chemicalforever {]}}% {} needed!
\def\1{\chemicaloxidation\relax1}%
\def\2{\chemicaloxidation\relax2}%
\def\3{\chemicaloxidation\relax3}%
\def\4{\chemicaloxidation\relax4}%
\def\5{\chemicaloxidation\relax5}%
\def\6{\chemicaloxidation\relax6}%
\def\7{\chemicaloxidation\relax7}%
\def\X{\chemicaltighttext}%
\def\T{\chemicaltop}%
\def\B{\chemicalbottom}%
\def\L{\chemicalleft}%
\def\LC{\chemicalleftcentered}%
\def\R{\chemicalright}%
\def\RC{\chemicalrightcentered}%
\def\TL{\chemicaltopleft}%
\def\BL{\chemicalbottomleft}%
\def\TR{\chemicaltopright}%
\def\BR{\chemicalbottomright}%
\def\LT{\chemicallefttop}%
\def\LB{\chemicalleftbottom}%
\def\RT{\chemicalrighttop}%
\def\RB{\chemicalrightbottom}%
\def\SL{\chemicalsmashedleft}%
\def\SM{\chemicalsmashedmiddle}%
\def\SR{\chemicalsmashedright}}

% \reversechemical#1#2#3
%
% #1: prefix
% #2: volgnummer enz
% #3: tegengestelde volgnummers

\def\reversechemical#1#2#3%
{\def\doprocess[##1##2]%
{\doifchemicalnumber{##1}{#1#2}%
{\getfromcommalist[#3][##1]%
\let\reversechemicalaction=\commalistelement
\processchemical[#1\reversechemicalaction##2]}}%
\doprocess[#2]}

% \processunknownchemical[#1????][#2]
%
% #1: bindingen enz.
% #2: atomen enz.

\def\defaultchemical%
{SIX}

\def\processunknownchemical[#1????][#2]%
{\processaction
[#1]
[ SAVE=>\executechemicalSAVE,
RESTORE=>\executechemicalRESTORE,
HIGH=>\sethighsubscripts,
LOW=>\setlowsubscripts,
\s!default=>,
\s!unknown=>\doifdefinedelse{\s!executechemical#1}
{\def\chemicalrotation{1}%
\def\chemicaloffset{0}%
\doifdefined{\s!executechemical#1}
{\getvalue{\s!executechemical#1}[#2]}%
\@@chemicalpostponed}
{\getpredefinedchemical{#1}}]}

\newcount\chemicalstack % tzt \newwounter

\setvalue{\s!chemical\c!x1}{0}
\setvalue{\s!chemical\c!y1}{0}

\def\executechemicalSAVE%
{%\writestatus{ppchtex}{saving \the\horchemical,\the\verchemical}%
\advance\chemicalstack by 1
\letvalue {\s!chemical n\the\chemicalstack}=\chemicalname
%\letvalue {\s!chemical p\the\chemicalstack}=\@@chemicalpostponed
\setevalue{\s!chemical x\the\chemicalstack}{\the\horchemical}%
\setevalue{\s!chemical y\the\chemicalstack}{\the\verchemical}}

\def\restorechemicalvalues#1%
{\let\oldprocesschemical=\processchemical
\doifdefined{\s!executechemical#1}{\getvalue{\s!executechemical#1}[]}%
\let\processchemical=\oldprocesschemical}

\def\executechemicalRESTORE%
{\ifnum\chemicalstack=0\relax
\horchemical=\getvalue{\s!chemical x1}\relax
\verchemical=\getvalue{\s!chemical y1}\relax
\else
\restorechemicalvalues{\getvalue{\s!chemical n\the\chemicalstack}}%
%\@EA\let\@EA\@@chemicalpostponed\@EA=\csname\s!chemical p\the\chemicalstack\endcsname
\let\@@chemicalpostponed=\relax
\horchemical=\getvalue{\s!chemical x\the\chemicalstack}\relax
\verchemical=\getvalue{\s!chemical y\the\chemicalstack}\relax
\advance\chemicalstack by -1
\fi
\restorechemicalcoordinates}

% De onderstaande macro's zijn verantwoordelijk voor het zetten
% van de + en pijlen. De +, en dus ook de pijlen, worden omhoog
% gehaald. Dit oogt m.i. fraaier.

\def\chemicalinnerclip#1%
{{\setbox0=\hbox{#1}\ht0\ht\strutbox\dp0\dp\strutbox\box0}}

\def\chemicalraise#1#2%
{\chemicalinnerclip
{\setbox0=\hbox{$#1+$}%
\raise\dp0\hbox{$#1#2$}}}

\def\chemicalinnersign#1% todo: \@@chemicaltextcolor
{\chemicalraise{\@@localchemicalstyle}{#1}}

\def\chemicaloutersign#1%
{\chemicalraise{}{\@@dochemicalcolor#1}}

\def\chemicalsingleinnerarrow#1#2%
{\chemicalraise{\@@localchemicalstyle}{\longrightarrow}}

\def\chemicaldoubleinnerarrow#1#2% todo: \@@chemicaltextcolor
{\chemicalinnerclip
{\lower.2ex\hbox
{\setbox0=\hbox{$\@@localchemicalstyle\longrightarrow$}%
\setbox2=\hbox{$\@@localchemicalstyle\longleftarrow$}%
\wd0=0pt\raise\ht0\box0\box2}}}

\def\chemicaltwintipinnerarrow#1#2% todo: \@@chemicaltextcolor
{\chemicalinnerclip
{\setbox0=\hbox{\chemicalraise{\@@localchemicalstyle}{\longrightarrow}}%
\setbox2=\hbox{\chemicalraise{\@@localchemicalstyle}{\longleftarrow}}%
\wd0=0pt\box0\box2}}

\def\dochemicalouterarrow#1#2#3%
{\bgroup
\setbox0=\hbox{$\longrightarrow$}%
\setbox2=\hbox{$\@@dochemicalstyle{\scriptstyle\quad#2\quad}$}%
\setbox4=\hbox{$\@@dochemicalstyle{\scriptstyle\quad#3\quad}$}%
\dimen2=\wd0 % \dimen0 is used elsewhere
\ifdim\wd2>\dimen2 \dimen0=\wd2 \fi
\ifdim\wd4>\dimen2 \dimen0=\wd4 \fi
\chemicaloutermolecule
{#1}
{\ifdim\ht2>\!!zeropoint\box2\fi} % expands to \empty in test
{\ifdim\ht4>\!!zeropoint\box4\fi}% % expands to \empty in test
\egroup}

\def\chemicalsingleouterarrow%
{\dochemicalouterarrow
{\hbox to \dimen2{\rightarrowfill}}}

\def\chemicaldoubleouterarrow%
{\dochemicalouterarrow
{\lower.5\ht0\vbox
{\offinterlineskip
\hbox to \dimen2{\rightarrowfill}
\hbox to \dimen2{\leftarrowfill}}}}

\def\chemicaltwintipouterarrow%
{\dochemicalouterarrow
{\hbox
{\hbox to \dimen2{\rightarrowfill}%
\hskip-\dimen2
\hbox to \dimen2{\leftarrowfill}}}}

\def\chemicalinnermolecule#1#2#3% no mathop here, can generate space
{\chemicalspace % todo: \@@chemicaltextcolor
\chemicalinnerclip
{\dosetsubscripts
$\@@dochemicalstyle{\@@localchemicalstyle\strut#1}$%
\doresetsubscripts}%
\chemicalspace}

\def\chemicaloutermolecule#1#2#3%
{\chemicalspace
\bgroup
\@@dochemicalcolor
\setbox0=\hbox % else the font is reset
{\dosetsubscripts
\hbox{$\@@dochemicalstyle{\strut#1}$}%
\doresetsubscripts}%
\mathop{\box0}%
\ifthirdargument
\doifnot{#2}{}
{^{\@@dochemicalstyle{\strut#2}}}%
\doifnot{#3}{}
{_{\@@dochemicalstyle{\strut#3}}}%
\else
\doifnot{#2}{}
{_{\@@dochemicalstyle{\strut#2}}}%
\fi
\egroup
\chemicalspace}

\def\chemicalsinglepicturearrow#1%
{\lower.5ex\hbox
{\@@dochemicalstyle
$\chemicalspace
\buildrel
\@@dochemicalstyle{\scriptstyle\quad#1\quad}%
\over{\overrightarrow
{\hphantom{\@chemicalstyle{\scriptstyle\quad#1\quad}}}}%
\chemicalspace$}}

\def\chemicaldoublepicturearrow#1%
{\lower.5ex\hbox
{\@@dochemicalstyle
$\chemicalspace
\buildrel
\@@dochemicalstyle{\scriptstyle\quad#1\quad}%
\over{\overrightarrow{\overleftarrow
{\hphantom{\@@dochemicalstyle{\scriptstyle\quad#1\quad}}}}}%
\chemicalspace$}}

% Bij de in-line bindingen wordt gebruik gemaakt van
% een \hrule. De maatvoering wordt bepaald door een
% kunstmatige em (\wd0).

\def\somechemicalbond%
{\hrule width \wd0 height .4pt}

\def\dochemicalbonds#1#2#3% todo: \@@chemicaltextstyle
{{\setbox0=\hbox
{${\@@localchemicalstyle M}$}%
\vbox to \ht0
{\@@dochemicalcolor
\hsize\wd0
\vskip.1\wd0#1\vfill#2\vfill#3\vskip.1\wd0}}}

\def\singlechemicalbond%
{\dochemicalbonds{}{\somechemicalbond}{}}

\def\doublechemicalbond%
{\dochemicalbonds{\somechemicalbond}{}{\somechemicalbond}}

\def\triplechemicalbond%
{\dochemicalbonds{\somechemicalbond}{\somechemicalbond}{\somechemicalbond}}

% In plaats van \def\naam{\chemie[...]...} kan beter gebruik
% worden gemaakt van het commando
%
% \definieerchemie[naam]{commando's}
%
% De naam krijgt, om problemen met bestaande macro's te
% voorkomen, een prefix. Bij het ophalen van een commando
% worden beide definities afgehandeld.

\def\dodefinechemical[#1]#2%
{\doifdefined{\??chemical#1}
{\writestatus{ppchtex}{chemical definition #1 is redefined}}%
\setvalue{\??chemical#1}{#2}}

\def\definechemical%
{\dosingleargument\dodefinechemical}

\def\getpredefinedchemical#1%
{\doifdefinedelse{\??chemical#1}
{\getvalue{\??chemical#1}}
{\doifdefinedelse{#1}
{\getvalue{#1}}
{\writestatus{ppchtex}{unknown chemical definition #1}}}}

% Hieronder zijn de definities van de structuren opgenomen. De
% naam van de structuur is als volgt opgebouwd:
%
% \executechemicalNUMBER[#1]
%
% waarbij [#1] betrekking heeft op de tekstelementen van \chemie,
% de [tweede lijst] dus.
%
% De aan \chemie[#1][#2] meegegeven lijst van segmenten wordt
% deels door de in \execute gedefinieerde macro's afgehandeld,
% deels door algemene macro's. Segmenten hebben de vorm:
%
% [+|-|]identifier[X|XYZ|X..Y]
%
% Voorbeelden van segmenten zijn:
%
% R1
% R1..4
% R135
% -R1
% +R35

\setchemicalmaximum 0

\def\processchemical[#1]%
{\unknownchemical{#1}}

\def\setchemicalname#1 %
{\def\chemicalname{#1}}

\let\chemicalname=\s!unknown

% Vooruitlopend op een gedetailleerde documentatie, zijn hier
% vast enkele gebruikte afmetingen:
%
% lengte radikalen : 500
% afstand radikalen : 100
% afstand dubbele radikalen : 260
% afstand substituenten : +125

\def\executechemicalONE[#1]%
{\setchemicalname ONE
%
\setchemicalmaximum 8
\setchemicaldistance 0
\setchemicalsubstitute 625
\setchemicaldirection 303
%
\setchemicalrotation 1 1 0 1 0 1 0 1 0
\setchemicalrotation 2 0.707 -0.707 0.707 -0.707 0.707 -0.707 0.707 -0.707
\setchemicalrotation 3 0 -1 0 -1 0 -1 0 -1
\setchemicalrotation 4 -0.707 -0.707 -0.707 -0.707 -0.707 -0.707 -0.707 -0.707
\setchemicalrotation 5 -1 0 -1 0 -1 0 -1 0
\setchemicalrotation 6 -0.707 0.707 -0.707 0.707 -0.707 0.707 -0.707 0.707
\setchemicalrotation 7 0 1 0 1 0 1 0 1
\setchemicalrotation 8 0.707 0.707 0.707 0.707 0.707 0.707 0.707 0.707
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 45 135 225 315
\setchemicalangle 3 90 180 270 0
\setchemicalangle 4 135 225 315 45
\setchemicalangle 5 180 270 0 90
\setchemicalangle 6 225 315 45 135
\setchemicalangle 7 270 0 90 180
\setchemicalangle 8 315 45 135 225
%
\setchemicaltranslate 1 -1000 0
\setchemicaltranslate 2 -1000 1000
\setchemicaltranslate 3 0 1000
\setchemicaltranslate 4 1000 1000
\setchemicaltranslate 5 1000 0
\setchemicaltranslate 6 1000 -1000
\setchemicaltranslate 7 0 -1000
\setchemicaltranslate 8 -1000 -1000
%
\setchemicallinesegment SB 300 0 700 0
\setchemicallinesegment DB1 300 50 700 50
\setchemicallinesegment DB2 300 -50 700 -50
%
\setchemicallinesegment EP 200 125 200 -125
\setchemicaltextelement ES 200 0
\setchemicaltextelement ED1 200 50
\setchemicaltextelement ED2 200 -50
\setchemicaltextelement ET1 200 75
\setchemicaltextelement ET2 200 0
\setchemicaltextelement ET3 200 -75
\setchemicaltextelement HB1 300 0
\setchemicaltextelement HB2 475 0
\setchemicaltextelement HB3 650 0
%
\setchemicaltextelement Z 800 0
\setchemicaltextelement RZ 950 0
\setchemicaltextelement ZN 500 0
\setchemicaltextelement ZTN 500 150
\setchemicaltextelement ZBN 500 -150
%
\def\processchemical[##1##2##3##4##5]%
{\doprocesschemical[##1##2##3##4##5]
{\processaction
[##1##2##3##4##5]
[ PB:##4##5=>\beginchemicalpicture{##4##5},
PE????=>\endchemicalpicture,
SUB##4##5=>\processchemicalsubstitute{##4##5},
ADJ##4##5=>\processchemicaldistance{##4##5},
MOV##4##5=>\processchemicaltranslate{##4##5},
DIR##4##5=>\processchemicaldirection{##4##5},
OFF##4##5=>\processchemicaloffset{##4##5},
CCD##4##5=>\processchemicaldottsegment{CC}{##4##5},
LDD##4##5=>\processchemicaldashedlinesegment{DB1}{##4##5}%
\processchemicallinesegment{DB2}{##4##5},
RDD##4##5=>\processchemicallinesegment{DB1}{##4##5}%
\processchemicaldashedlinesegment{DB2}{##4##5},
OF##3:##5=>\processchemicalphantom{##3}{##5},
OE##3##4##5=>\processchemicalopenend{OE}{##3##4##5},
EP##3##4##5=>\processchemicallinesegment{EP}{##3##4##5},
ES##3##4##5=>\processchemicaltextconstant{ES}{##3##4##5}{\hbox{$\cdot$}}{0},
ED##3##4##5=>\processchemicaltextconstant{ED}{##3##4##5}{\hbox{$\cdot$}}{0},
ET##3##4##5=>\processchemicaltextconstant{ET}{##3##4##5}{\hbox{$\cdot$}}{0},
HB##3##4##5=>\processchemicaltextconstant{HB}{##3##4##5}{\hbox{$\cdot$}}{0},
SB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5},
DB##3##4##5=>\processchemicallinesegment{DB}{##3##4##5},
SB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5},
BB##3##4##5=>\processchemicaldeltalinesegment{SB}{##3##4##5},
SD##3##4##5=>\processchemicaldashedlinesegment{SB}{##3##4##5},
TB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5}%
\processchemicallinesegment{DB}{##3##4##5},
CZ##3##4##5=>\processchemicaltextelement{RZ}{##3##4##5}{#1}{0}{},
ZTN##4##5=>\processchemicalsmalltextconstant{ZTN}{##4##5}{\chemicaltextelementnumber}{0},
ZTT##4##5=>\processchemicalsmalltextelement{ZTN}{##4##5}{#1}{0}{},
ZBN##4##5=>\processchemicalsmalltextconstant{ZBN}{##4##5}{\chemicaltextelementnumber}{0},
ZBT##4##5=>\processchemicalsmalltextelement{ZBN}{##4##5}{#1}{0}{},
ZN##3##4##5=>\processchemicaltextconstant{ZN}{##3##4##5}{\chemicaltextelementnumber}{0},
ZT##3##4##5=>\processchemicaltextelement{ZN}{##3##4##5}{#1}{0}{},
Z##2##3##4##5=>\processchemicaltextelement{Z}{##2##3##4##5}{#1}{0}
{l,l,t,r,r,r,b,l},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}}

\def\executechemicalTHREE[#1]%
{\setchemicalname THREE
%
\setchemicalmaximum 3
\setchemicaldistance 289
\setchemicalsubstitute 952
%
\setchemicalrotation 1 1 0 0 -1 -1 0 0 1
\setchemicalrotation 2 -0.5 -0.866 -0.866 0.5 0.5 0.866 0.866 -0.5
\setchemicalrotation 3 -0.5 0.866 0.866 0.5 0.5 -0.866 -0.866 -0.5
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 120 210 300 30
\setchemicalangle 3 240 330 60 150
%
\setchemicaltranslate 1 -1000 0
\setchemicaltranslate 2 0 1000
\setchemicaltranslate 3 1000 0
\setchemicaltranslate 4 0 -1000
%
\setchemicallinesegment B 577 0 -289 -500
\setchemicallinesegment SB 352 -130 -64 -370
\setchemicallinesegment -SB 352 -130 -289 -500
\setchemicallinesegment +SB 577 0 -64 -370
\setchemicallinesegment DB1 327 -87 -89 -327
\setchemicallinesegment DB2 377 -172 -39 -413
\setchemicallinesegment R 577 0 1077 0
\setchemicallinesegment -R 577 0 1010 250
\setchemicallinesegment +R 577 0 1010 -250
\setchemicallinesegment ER1 577 50 1077 50
\setchemicallinesegment ER2 577 -50 1077 -50
\setchemicallinesegment SR 837 0 1077 0
\setchemicallinesegment -SR 802 130 1010 250
\setchemicallinesegment +SR 802 -130 1010 -250
\setchemicallinesegment DR1 837 50 1077 50
\setchemicallinesegment DR2 837 -50 1077 -50
%
\setchemicaltextelement Z 577 0
\setchemicaltextelement RZ 1177 0
\setchemicaltextelement -RZ 1097 300
\setchemicaltextelement +RZ 1097 -300
\setchemicaltextelement CRZ 1077 0
%
\def\processchemical[##1##2##3##4]%
{\processaction
[##1##2##3##4]
[ ROT##4=>\processchemicalrotation{##4},
MOV##4=>\processchemicaltranslate{##4},
SUB##4=>\processchemicalsubstitute{##4},
ADJ##4=>\processchemicaldistance{##4},
-RZ##4=>\processchemicaltextelement{-RZ}{##4}{#1}{3}
{l,t,r, l,r,l, r,b,l, r,l,r},
+RZ##4=>\processchemicaltextelement{+RZ}{##4}{#1}{3}
{l,r,b, r,r,l, r,l,t, l,l,r},
-SB##4=>\processchemicallinesegment{-SB}{##4},
+SB##4=>\processchemicallinesegment{+SB}{##4},
-SR##4=>\processchemicallinesegment{-SR}{##4},
+SR##4=>\processchemicallinesegment{+SR}{##4},
CRZ##4=>\processchemicaltextelement{CRZ}{##4}{#1}{0}
{},
DB##3##4=>\processchemicallinesegment{DB}{##3##4},
DR##3##4=>\processchemicallinesegment{DR}{##3##4},
RZ##3##4=>\processchemicaltextelement{RZ}{##3##4}{#1}{3}
{l,r,r, t,r,l, r,l,l, b,l,r},
ER##3##4=>\processchemicallinesegment{ER}{##3##4},
SB##3##4=>\processchemicallinesegment{SB}{##3##4},
SR##3##4=>\processchemicallinesegment{SR}{##3##4},
-R##3##4=>\processchemicallinesegment{-R}{##3##4},
+R##3##4=>\processchemicallinesegment{+R}{##3##4},
B##2##3##4=>\processchemicallinesegment{B}{##2##3##4},
R##2##3##4=>\processchemicallinesegment{R}{##2##3##4},
Z##2##3##4=>\processchemicaltextelement{Z}{##2##3##4}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

\def\executechemicalFOUR[#1]%
{\setchemicalname FOUR
%
\setchemicalmaximum 4
\setchemicaldistance 500
\setchemicalsubstitute 0
%
\setchemicalrotation 1 1 0 0 -1 -1 0 0 1
\setchemicalrotation 2 0 -1 -1 0 0 1 1 0
\setchemicalrotation 3 -1 0 0 1 1 0 0 -1
\setchemicalrotation 4 0 1 1 0 0 -1 -1 0
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 90 180 270 0
\setchemicalangle 3 180 270 0 90
\setchemicalangle 4 270 0 90 180
%
\setchemicaltranslate 1 -1000 0
\setchemicaltranslate 2 0 1000
\setchemicaltranslate 3 1000 0
\setchemicaltranslate 4 0 -1000
%
\setchemicallinesegment B 500 500 500 -500
\setchemicallinesegment SB 500 240 500 -240
\setchemicallinesegment -SB 500 240 500 -500
\setchemicallinesegment +SB 500 500 500 -240
\setchemicallinesegment DB1 450 240 450 -240
\setchemicallinesegment DB2 550 240 550 -240
\setchemicallinesegment EB 360 300 360 -300
\setchemicallinesegment R 500 500 854 854
\setchemicallinesegment -R 500 500 500 1000
\setchemicallinesegment +R 500 500 1000 500
\setchemicallinesegment ER1 465 535 819 889
\setchemicallinesegment ER2 535 465 889 819
\setchemicallinesegment SR 684 684 854 854
\setchemicallinesegment -SR 500 760 500 1000
\setchemicallinesegment +SR 760 500 1000 500
\setchemicallinesegment DR1 649 719 819 889
\setchemicallinesegment DR2 719 649 889 819
%
\setchemicaltextelement Z 500 500
\setchemicaltextelement RZ 925 925
\setchemicaltextelement -RZ 500 1100
\setchemicaltextelement +RZ 1100 500
\setchemicaltextelement CRZ 1038 1038
%
\setchemicaltextelement ZN 350 350
%
\def\processchemical[##1##2##3##4]%
{\processaction
[##1##2##3##4]
[ PB:##4=>\beginchemicalpicture{##4},
PE????=>\endchemicalpicture,
ROT##4=>\processchemicalrotation{##4},
SUB##4=>\processchemicalsubstitute{##4},
ADJ##4=>\processchemicaldistance{##4},
MOV##4=>\processchemicaltranslate{##4},
-RZ##4=>\processchemicaltextelement{-RZ}{##4}{#1}{4}
{b,l,t,r, l,t,r,b, t,r,b,l, r,b,l,t},
+RZ##4=>\processchemicaltextelement{+RZ}{##4}{#1}{4}
{l,t,r,b, t,r,b,l, r,b,l,t, b,l,t,r},
-SB##4=>\processchemicallinesegment{-SB}{##4},
+SB##4=>\processchemicallinesegment{+SB}{##4},
-SR##4=>\processchemicallinesegment{-SR}{##4},
+SR##4=>\processchemicallinesegment{+SR}{##4},
CRZ##4=>\processchemicaltextelement{CRZ}{##4}{#1}{0}{},
ZN##3##4=>\processchemicaltextconstant{ZN}{##3##4}{\chemicaltextelementnumber}{0},
ZT##3##4=>\processchemicaltextelement{ZN}{##3##4}{#1}{0}{},
DB##3##4=>\processchemicallinesegment{DB}{##3##4},
DR##3##4=>\processchemicallinesegment{DR}{##3##4},
EB##3##4=>\processchemicallinesegment{EB}{##3##4},
ER##3##4=>\processchemicallinesegment{ER}{##3##4},
RZ##3##4=>\processchemicaltextelement{RZ}{##3##4}{#1}{4}
{lb,lt,rt,rb, lt,rt,rb,lb, rt,rb,lb,lt, rb,lb,lt,rt},
SB##3##4=>\processchemicallinesegment{SB}{##3##4},
SR##3##4=>\processchemicallinesegment{SR}{##3##4},
-R##3##4=>\processchemicallinesegment{-R}{##3##4},
+R##3##4=>\processchemicallinesegment{+R}{##3##4},
B##2##3##4=>\processchemicallinesegment{B}{##2##3##4},
R##2##3##4=>\processchemicallinesegment{R}{##2##3##4},
Z##2##3##4=>\processchemicaltextelement{Z}{##2##3##4}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

\def\executechemicalFIVE[#1]%
{\setchemicalname FIVE
%
\setchemicalmaximum 5
\setchemicaldistance 688
\setchemicalsubstitute 1226
%
\setchemicalrotation 1 1 0 0 -1 -1 0 0 1
\setchemicalrotation 2 0.309 -0.951 -0.951 -0.309 -0.309 0.940 0.951 0.309
\setchemicalrotation 3 -0.809 -0.588 -0.588 0.809 0.809 0.588 0.588 -0.809
\setchemicalrotation 4 -0.809 0.588 0.588 0.809 0.809 -0.588 -0.588 -0.809
\setchemicalrotation 5 0.309 0.951 0.951 -0.309 -0.309 -0.951 -0.951 0.309
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 72 162 252 342
\setchemicalangle 3 144 234 324 54
\setchemicalangle 4 216 306 36 126
\setchemicalangle 5 288 18 108 198
%
\setchemicaltranslate 1 -1376 0
\setchemicaltranslate 2 -425 1304
\setchemicaltranslate 3 1113 809
\setchemicaltranslate 4 1113 -809
\setchemicaltranslate 5 -425 -1304
%
\setchemicallinesegment A 1188 500 1188 -500
\setchemicallinesegment B 688 500 688 -500
\setchemicallinesegment S -263 808 688 -500
\setchemicallinesegment SS -116 606 541 -298
\setchemicallinesegment -SS -263 808 541 -298
\setchemicallinesegment +SS -116 606 688 -500
\setchemicallinesegment SB 688 240 688 -240
\setchemicallinesegment -SB 688 240 688 -500
\setchemicallinesegment +SB 688 500 688 -240
\setchemicallinesegment DB1 638 240 638 -240
\setchemicallinesegment DB2 738 240 738 -240
\setchemicallinesegment EB 548 340 548 -340
\setchemicallinesegment R 688 500 1093 794
\setchemicallinesegment -R 688 500 688 1000
\setchemicallinesegment +R 688 500 1163 345
\setchemicallinesegment ER1 659 540 1064 834
\setchemicallinesegment ER2 727 460 1122 754
\setchemicallinesegment SR 898 653 1093 794
\setchemicallinesegment -SR 688 760 688 1000
\setchemicallinesegment +SR 935 420 1163 345
\setchemicallinesegment DR1 869 693 1064 834
\setchemicallinesegment DR2 927 613 1122 754
%
\setchemicaltextelement Z 688 500
\setchemicaltextelement RZ 1188 863
\setchemicaltextelement -RZ 688 1100
\setchemicaltextelement +RZ 1258 315
\setchemicaltextelement CRZ 1323 947
%
\setchemicalcircsegment C -36 36 590 72 475 -345
\setchemicalcircsegment CC -72 0 590 72 182 -561
%
\setchemicaltextelement ZN 468 350
\setchemicaltextelement RN 860 625 % 1.25 Z
\setchemicaltextelement RTN 785 728 % .12 / 103 75
\setchemicaltextelement RBN 935 522
%
\def\processchemical[##1##2##3##4]%
{\processaction
[##1##2##3##4]
[ FRONT????=>{\executechemicalFIVEFRONT[#1]},
PB:##4=>\beginchemicalpicture{##4},
PE????=>\endchemicalpicture,
ROT##4=>\processchemicalrotation{##4},
SUB##4=>\processchemicalsubstitute{##4},
ADJ##4=>\processchemicaldistance{##4},
MOV##4=>\processchemicaltranslate{##4},
-RZ##4=>\processchemicaltextelement{-RZ}{##4}{#1}{5}
{b,l,t,r,r, l,t,r,r,l, t,r,r,l,l, r,b,l,t,r},
+RZ##4=>\processchemicaltextelement{+RZ}{##4}{#1}{5}
{l,t,r,r,b, t,r,r,l,l, r,r,l,l,r, b,l,l,r,r},
-SB##4=>\processchemicallinesegment{-SB}{##4},
+SB##4=>\processchemicallinesegment{+SB}{##4},
-SR##4=>\processchemicallinesegment{-SR}{##4},
+SR##4=>\processchemicallinesegment{+SR}{##4},
-RD##4=>\processchemicaldashedlinesegment{-R}{##4},
+RD##4=>\processchemicaldashedlinesegment{+R}{##4},
-RB##4=>\processchemicaldeltalinesegment{-R}{##4},
+RB##4=>\processchemicaldeltalinesegment{+R}{##4},
CRZ##4=>\processchemicaltextelement{CRZ}{##4}{#1}{0}{},
RTN##4=>\processchemicaltextconstant{RTN}{##4}{\chemicaltextelementnumber}{0},
RTT##4=>\processchemicaltextelement{RTN}{##4}{#1}{0}{},
RBN##4=>\processchemicaltextconstant{RBN}{##4}{\chemicaltextelementnumber}{0},
RBT##4=>\processchemicaltextelement{RBN}{##4}{#1}{0}{},
-SS##4=>\processchemicallinesegment{-SS}{##4},
+SS##4=>\processchemicallinesegment{+SS}{##4},
CCD##4=>\processchemicaldottsegment{CC}{##4},
SS##3##4=>\processchemicallinesegment{SS}{##3##4},
RD##3##4=>\processchemicaldashedlinesegment{R}{##3##4},
RB##3##4=>\processchemicaldeltalinesegment{R}{##3##4},
ZN##3##4=>\processchemicaltextconstant{ZN}{##3##4}{\chemicaltextelementnumber}{0},
ZT##3##4=>\processchemicaltextelement{ZN}{##3##4}{#1}{0}{},
RN##3##4=>\processchemicaltextconstant{RN}{##3##4}{\chemicaltextelementnumber}{0},
RT##3##4=>\processchemicaltextelement{RN}{##3##4}{#1}{0}{},
AU##3##4=>\processchemicaluparrowsegment{A}{##3##4},
AD##3##4=>\processchemicaldownarrowsegment{A}{##3##4},
CC##3##4=>\processchemicalcircsegment{CC}{##3##4},
CD##3##4=>\processchemicaldottsegment{C}{##3##4},
DB##3##4=>\processchemicallinesegment{DB}{##3##4},
DR##3##4=>\processchemicallinesegment{DR}{##3##4},
EB##3##4=>\processchemicallinesegment{EB}{##3##4},
ER##3##4=>\processchemicallinesegment{ER}{##3##4},
RZ##3##4=>\processchemicaltextelement{RZ}{##3##4}{#1}{5}
{l,l,r,r,r, l,r,r,b,l, r,r,b,l,t, r,l,l,t,r},
SB##3##4=>\processchemicallinesegment{SB}{##3##4},
SR##3##4=>\processchemicallinesegment{SR}{##3##4},
-R##3##4=>\processchemicallinesegment{-R}{##3##4},
+R##3##4=>\processchemicallinesegment{+R}{##3##4},
B##2##3##4=>\processchemicallinesegment{B}{##2##3##4},
C##2##3##4=>\processchemicalcircsegment{C}{##2##3##4},
R##2##3##4=>\processchemicallinesegment{R}{##2##3##4},
S##2##3##4=>\processchemicallinesegment{S}{##2##3##4},
Z##2##3##4=>\processchemicaltextelement{Z}{##2##3##4}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

\def\executechemicalSIX[#1]%
{\setchemicalname SIX
%
\setchemicalmaximum 6
\setchemicalsubstitute 1375
\setchemicaldistance 866
%
\setchemicalrotation 1 1 0 0 -1 -1 0 0 1
\setchemicalrotation 2 0.5 -0.866 -0.866 -0.5 -0.5 0.866 0.866 0.5
\setchemicalrotation 3 -0.5 -0.866 -0.866 0.5 0.5 0.866 0.866 -0.5
\setchemicalrotation 4 -1 0 0 1 1 0 0 -1
\setchemicalrotation 5 -0.5 0.866 0.866 0.5 0.5 -0.866 -0.866 -0.5
\setchemicalrotation 6 0.5 0.866 0.866 -0.5 -0.5 -0.866 -0.866 0.5
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 60 150 240 330
\setchemicalangle 3 120 210 300 30
\setchemicalangle 4 180 270 0 90
\setchemicalangle 5 240 330 60 150
\setchemicalangle 6 300 30 120 210
%
\setchemicaltranslate 1 -1732 0
\setchemicaltranslate 2 -866 1500
\setchemicaltranslate 3 866 1500
\setchemicaltranslate 4 1732 0
\setchemicaltranslate 5 866 -1500
\setchemicaltranslate 6 -866 -1500
%
\setchemicallinesegment A 1386 500 1386 -500
\setchemicallinesegment S 0 1000 866 -500
\setchemicallinesegment SS 125 783 741 -283
\setchemicallinesegment -SS 0 1000 741 -283
\setchemicallinesegment +SS 125 783 866 -500
\setchemicallinesegment B 866 500 866 -500
\setchemicallinesegment SB 866 240 866 -240
\setchemicallinesegment -SB 866 240 866 -500
\setchemicallinesegment +SB 866 500 866 -240
\setchemicallinesegment DB1 816 240 816 -240
\setchemicallinesegment DB2 916 240 916 -240
\setchemicallinesegment EB 726 340 726 -340
\setchemicallinesegment R 866 500 1299 750
\setchemicallinesegment -R 866 500 866 1000
\setchemicallinesegment +R 866 500 1299 250
\setchemicallinesegment ER1 841 543 1274 793
\setchemicallinesegment ER2 891 457 1324 707
\setchemicallinesegment SR 1091 630 1299 750
\setchemicallinesegment -SR 866 740 866 1000
\setchemicallinesegment +SR 1091 370 1299 250
\setchemicallinesegment DR1 1066 673 1274 793
\setchemicallinesegment DR2 1116 588 1324 707
\setchemicallinesegment MID1 0 1000 -150 200
\setchemicallinesegment MID2 0 -1000 -150 -200
\setchemicallinesegment MIDS1 0 1000 -180 0
\setchemicallinesegment MIDS2 0 -1000 -180 0
%
\setchemicalcircsegment C -30 30 700 60 600 -346
\setchemicalcircsegment CC -60 0 700 60 350 -606
%
\setchemicaltextelement Z 866 500
\setchemicaltextelement RZ 1386 800
\setchemicaltextelement -RZ 866 1100
\setchemicaltextelement +RZ 1386 200
\setchemicaltextelement CRZ 1524 880
\setchemicaltextelement MIDZ -150 0
%
\setchemicaltextelement ZN 589 350
\setchemicaltextelement RN 1083 625 % 1.25 Z
\setchemicaltextelement RTN 1008 755 % .12 / 130 75
\setchemicaltextelement RBN 1158 495
%
\def\processchemical[##1##2##3##4##5]%
{\processaction
[##1##2##3##4##5]
[ FRONT????=>{\executechemicalSIXFRONT[#1]},
MID????=>\processchemicallinesegment{MID}{1????},
MIDS????=>\processchemicallinesegment{MIDS}{1????},
MIDZ????=>\processchemicaltextelement{MIDZ}{1????}{#1}{0}{},
PB:##4##5=>\beginchemicalpicture{##4##5},
PE????=>\endchemicalpicture,
ROT##4##5=>\processchemicalrotation{##4##5},
SUB##4##5=>\processchemicalsubstitute{##4##5},
ADJ##4##5=>\processchemicaldistance{##4##5},
MOV##4##5=>\processchemicaltranslate{##4##5},
-RZ##4##5=>\processchemicaltextelement{-RZ}{##4##5}{#1}{6}
{b,l,l,t,r,r, l,l,r,r,r,l, t,r,r,b,l,l, r,r,l,l,l,r},
+RZ##4##5=>\processchemicaltextelement{+RZ}{##4##5}{#1}{6}
{l,t,r,r,b,l, r,r,r,l,l,l, r,b,l,l,t,r, l,l,l,r,r,r},
-SB##4##5=>\processchemicallinesegment{-SB}{##4##5},
+SB##4##5=>\processchemicallinesegment{+SB}{##4##5},
-SR##4##5=>\processchemicallinesegment{-SR}{##4##5},
+SR##4##5=>\processchemicallinesegment{+SR}{##4##5},
-RD##4##5=>\processchemicaldashedlinesegment{-R}{##4##5},
+RD##4##5=>\processchemicaldashedlinesegment{+R}{##4##5},
-RB##4##5=>\processchemicaldeltalinesegment{-R}{##4##5},
+RB##4##5=>\processchemicaldeltalinesegment{+R}{##4##5},
CRZ##4##5=>\processchemicaltextelement{CRZ}{##4##5}{#1}{0}{},
-SS##4##5=>\processchemicallinesegment{-SS}{##4##5},
+SS##4##5=>\processchemicallinesegment{+SS}{##4##5},
CCD##4##5=>\processchemicaldottsegment{CC}{##4##5},
RTN##4##5=>\processchemicaltextconstant{RTN}{##4##5}{\chemicaltextelementnumber}{0},
RTT##4##5=>\processchemicaltextelement{RTN}{##4##5}{#1}{0}{},
RBN##4##5=>\processchemicaltextconstant{RBN}{##4##5}{\chemicaltextelementnumber}{0},
RBT##4##5=>\processchemicaltextelement{RBN}{##4##5}{#1}{0}{},
SS##3##4##5=>\processchemicallinesegment{SS}{##3##4##5},
RD##3##4##5=>\processchemicaldashedlinesegment{R}{##3##4##5},
RB##3##4##5=>\processchemicaldeltalinesegment{R}{##3##4##5},
ZN##3##4##5=>\processchemicaltextconstant{ZN}{##3##4##5}{\chemicaltextelementnumber}{0},
ZT##3##4##5=>\processchemicaltextelement{ZN}{##3##4##5}{#1}{0}{},
RN##3##4##5=>\processchemicaltextconstant{RN}{##3##4##5}{\chemicaltextelementnumber}{0},
RT##3##4##5=>\processchemicaltextelement{RN}{##3##4##5}{#1}{0}{},
AU##3##4##5=>\processchemicaluparrowsegment{A}{##3##4##5},
AD##3##4##5=>\processchemicaldownarrowsegment{A}{##3##4##5},
CD##3##4##5=>\processchemicaldottsegment{C}{##3##4##5},
CC##3##4##5=>\processchemicalcircsegment{CC}{##3##4##5},
DB##3##4##5=>\processchemicallinesegment{DB}{##3##4##5},
EB##3##4##5=>\processchemicallinesegment{EB}{##3##4##5},
ER##3##4##5=>\processchemicallinesegment{ER}{##3##4##5},
RZ##3##4##5=>\processchemicaltextelement{RZ}{##3##4##5}{#1}{6}
{l,l,t,r,r,b, l,r,r,r,l,l, r,r,b,l,l,t, r,l,l,l,r,r},
SB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5},
SR##3##4##5=>\processchemicallinesegment{SR}{##3##4##5},
DR##3##4##5=>\processchemicallinesegment{DR}{##3##4##5},
-R##3##4##5=>\processchemicallinesegment{-R}{##3##4##5},
+R##3##4##5=>\processchemicallinesegment{+R}{##3##4##5},
B##2##3##4##5=>\processchemicallinesegment{B}{##2##3##4##5},
C##2##3##4##5=>\processchemicalcircsegment{C}{##2##3##4##5},
R##2##3##4##5=>\processchemicallinesegment{R}{##2##3##4##5},
S##2##3##4##5=>\processchemicallinesegment{S}{##2##3##4##5},
Z##2##3##4##5=>\processchemicaltextelement{Z}{##2##3##4##5}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}

\def\executechemicalSEVEN[#1]% incomplete !
{\setchemicalname SEVEN
%
\setchemicalmaximum 7
\setchemicalsubstitute -
\setchemicaldistance 1038
%
\setchemicalrotation 1 .623 .782 - - - - - -
\setchemicalrotation 2 -.223 .975 - - - - - -
\setchemicalrotation 3 -.901 .434 - - - - - -
\setchemicalrotation 4 -.901 -.434 - - - - - -
\setchemicalrotation 5 -.223 -.975 - - - - - -
\setchemicalrotation 6 .623 -.782 - - - - - -
\setchemicalrotation 7 1 0 - - - - - -
%
\setchemicalangle 1 0 - - -
\setchemicalangle 2 51.429 - - -
\setchemicalangle 3 102.857 - - -
\setchemicalangle 4 154.286 - - -
\setchemicalangle 5 205.714 - - -
\setchemicalangle 6 257.143 - - -
\setchemicalangle 7 308.571 - - -
%
\setchemicaltranslate 1 - -
\setchemicaltranslate 2 - -
\setchemicaltranslate 3 - -
\setchemicaltranslate 4 - -
\setchemicaltranslate 5 - -
\setchemicaltranslate 6 - -
\setchemicaltranslate 7 - -
%
\setchemicallinesegment B 1038 500 1038 -500
\setchemicallinesegment SB 1038 240 1038 -240
\setchemicallinesegment -SB 1038 240 1038 -500
\setchemicallinesegment +SB 1038 500 1038 -240
%
\setchemicaltextelement Z 1038 500
%
\def\processchemical[##1##2##3##4##5]%
{\processaction
[##1##2##3##4##5]
[ PB:##4##5=>\beginchemicalpicture{##4##5},
PE????=>\endchemicalpicture,
%ROT##4##5=>\processchemicalrotation{##4},
%SUB##4##5=>\processchemicalsubstitute{##4##5},
%ADJ##4##5=>\processchemicaldistance{##4##5},
%MOV##4##5=>\processchemicaltranslate{##4##5},
-SB##4##5=>\processchemicallinesegment{-SB}{##4##5},
+SB##4##5=>\processchemicallinesegment{+SB}{##4##5},
SB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5},
B##2##3##4##5=>\processchemicallinesegment{B}{##2##3##4##5},
Z##2##3##4##5=>\processchemicaltextelement{Z}{##2##3##4##5}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}

\def\executechemicalEIGHT[#1]% incomplete !
{\setchemicalname EIGHT
%
\setchemicalmaximum 8
%\setchemicalsubstitute 1307
\setchemicaldistance 1207
%
\setchemicalrotation 1 .707 .707 - - - - - -
\setchemicalrotation 2 0 1 - - - - - -
\setchemicalrotation 3 -.707 .707 - - - - - -
\setchemicalrotation 4 -1 0 - - - - - -
\setchemicalrotation 5 -.707 -.707 - - - - - -
\setchemicalrotation 6 0 -1 - - - - - -
\setchemicalrotation 7 .707 -.707 - - - - - -
\setchemicalrotation 8 1 0 - - - - - -
%
\setchemicalangle 1 45 - - -
\setchemicalangle 2 90 - - -
\setchemicalangle 3 135 - - -
\setchemicalangle 4 180 - - -
\setchemicalangle 5 225 - - -
\setchemicalangle 6 270 - - -
\setchemicalangle 7 315 - - -
\setchemicalangle 8 0 - - -
%
\setchemicaltranslate 1 -2414 0
\setchemicaltranslate 2 -1706 1706
\setchemicaltranslate 3 0 2414
\setchemicaltranslate 4 1706 1706
\setchemicaltranslate 5 2414 0
\setchemicaltranslate 6 1706 -1706
\setchemicaltranslate 7 0 -2414
\setchemicaltranslate 8 -1706 -1706
%
\setchemicallinesegment B 1207 500 1207 -500
\setchemicallinesegment SB 1207 240 1207 -240
\setchemicallinesegment -SB 1207 240 1207 -500
\setchemicallinesegment +SB 1207 500 1207 -240
%
\setchemicaltextelement Z 1207 500
%
\def\processchemical[##1##2##3##4##5]%
{\processaction
[##1##2##3##4##5]
[ PB:##4##5=>\beginchemicalpicture{##4##5},
PE????=>\endchemicalpicture,
%SUB##4##5=>\processchemicalsubstitute{##4##5},
ADJ##4##5=>\processchemicaldistance{##4##5},
MOV##4##5=>\processchemicaltranslate{##4##5},
-SB##4##5=>\processchemicallinesegment{-SB}{##4##5},
+SB##4##5=>\processchemicallinesegment{+SB}{##4##5},
SB##3##4##5=>\processchemicallinesegment{SB}{##3##4##5},
B##2##3##4##5=>\processchemicallinesegment{B}{##2##3##4##5},
Z##2##3##4##5=>\processchemicaltextelement{Z}{##2##3##4##5}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}

\def\executechemicalFIVEFRONT[#1]%
{\executechemicalFIVE[]%
%
\setchemicalname FIVEFRONT
%
\setchemicallinesegment -R 688 500 688 100
\setchemicallinesegment +R 688 500 688 900
%
\setchemicaltextelement -RZ 0 -1300
\setchemicaltextelement +RZ 0 1300
%
\def\processchemical[##1##2##3##4]%
{\def\chemicalrotation{2}%
\processaction
[##1##2##3##4]
[ -RZ##4=>\processchemicalunrotatedtextelement{Z}{-RZ}{##4}{#1}{5}
{,,,,, t,t,t,t,t},
+RZ##4=>\processchemicalunrotatedtextelement{Z}{+RZ}{##4}{#1}{5}
{,,,,, b,b,b,b,b},
-SB##4=>\processchemicallinesegment{-SB}{##4},
+SB##4=>\processchemicallinesegment{+SB}{##4},
SB##3##4=>\processchemicallinesegment{SB}{##3##4},
-R##3##4=>\processchemicalunrotatedlinesegment{t}{-R}{##3##4},
+R##3##4=>\processchemicalunrotatedlinesegment{b}{+R}{##3##4},
BB##3##4=>\processchemicalzlinesegment{B}{##3##4},
R##2##3##4=>\processchemicalunrotatedlinesegment{t}{-R}{##2##3##4}%
\processchemicalunrotatedlinesegment{b}{+R}{##2##3##4},
B##2##3##4=>\processchemicallinesegment{B}{##2##3##4},
Z##2##3##4=>\processchemicaltextelement{Z}{##2##3##4}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

\def\executechemicalSIXFRONT[#1]%
{\executechemicalSIX[]%
%
\setchemicalname SIXFRONT
%
\setchemicallinesegment -R 866 500 866 100
\setchemicallinesegment +R 866 500 866 900
%
\setchemicaltextelement -RZ 0 -1300
\setchemicaltextelement +RZ 0 1300
%
\def\processchemical[##1##2##3##4]%
{\def\chemicalrotation{2}%
\processaction
[##1##2##3##4]
[ -RZ##4=>\processchemicalunrotatedtextelement{Z}{-RZ}{##4}{#1}{6}
{,,,,,, t,t,t,t,t,t},
+RZ##4=>\processchemicalunrotatedtextelement{Z}{+RZ}{##4}{#1}{6}
{,,,,,, b,b,b,b,b,b},
-SB##4=>\processchemicallinesegment{-SB}{##4},
+SB##4=>\processchemicallinesegment{+SB}{##4},
SB##3##4=>\processchemicallinesegment{SB}{##3##4},
-R##3##4=>\processchemicalunrotatedlinesegment{t}{-R}{##3##4},
+R##3##4=>\processchemicalunrotatedlinesegment{b}{+R}{##3##4},
BB##3##4=>\processchemicalzlinesegment{B}{##3##4},
R##2##3##4=>\processchemicalunrotatedlinesegment{t}{-R}{##2##3##4}%
\processchemicalunrotatedlinesegment{b}{+R}{##2##3##4},
B##2##3##4=>\processchemicallinesegment{B}{##2##3##4},
Z##2##3##4=>\processchemicaltextelement{Z}{##2##3##4}{#1}{0}{},
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

% 1 : 0
% 2 : -115
% 3* : -195
% 3 : -165
% 4 : -245

\def\executechemicalCARBON[#1]%
{\setchemicalname CARBON
%
\setchemicalmaximum 4
\setchemicaldistance 0
\setchemicalsubstitute 0
%
\setchemicalrotation 1 1 0 0 -1 -1 0 0 1
\setchemicalrotation 2 -0.423 -0.906 -0.906 0.423 0.423 0.906 0.906 -0.423
\setchemicalrotation 3 -0.966 -0.259 -0.259 0.966 0.966 0.259 0.259 -0.966
\setchemicalrotation 3* -0.966 0.259 0.259 0.966 0.966 -0.259 -0.259 -0.966
\setchemicalrotation 4 -0.423 0.906 0.906 0.423 0.423 -0.906 -0.906 -0.423
%
\setchemicalangle 1 0 90 180 270
\setchemicalangle 2 115 205 295 25
\setchemicalangle 3 165 255 345 75
\setchemicalangle 3* 195 285 15 105
\setchemicalangle 4 245 335 65 155
%
\setchemicaltranslate 1 -1500 0
\setchemicaltranslate 2 0 1500
\setchemicaltranslate 3 1500 0
\setchemicaltranslate 4 0 -1500
%
\setchemicallinesegment B1 500 0 1000 0
\setchemicallinesegment B2 300 0 1000 0
\setchemicallinesegment B3 500 0 1000 0
\setchemicallinesegment B4 300 0 1000 0
%
\setchemicaltextelement Z 1100 0
%
\setchemicalcircsegment C 0 360 500 360 0 -500
%
\def\processchemical[##1##2##3##4##5]%
{\processaction
[##1##2##3##4##5]
[ MIR????=>\setchemicalmirror{3},
-MIR????=>\resetchemicalmirror{3},
*MIR????=>\togglechemicalmirror{3},
CB????=>\processlocalchemicals{B,C,Z},
C????=>\processchemicalcircsegment{C}{1????},
-ROT##5=>\reversechemical{ROT}{##5}{3,4,1,2},
ROT##4##5=>\processchemicalrotation{##4##5},
MOV##4##5=>\processchemicaltranslate{##4##5},
CB##3##4##5=>\processlocalchemicals
{ROT##3,C,B,Z2..4,
MOV##3,*MIR,-ROT##3,C,B,Z2..4},
B##2##3##4##5=>\processprivatechemicallinesegment{B}{##2##3##4##5},
Z##2##3##4##5=>\processchemicaltextelement{Z}{##2##3##4##5}{#1}{4}
{l,t,r,b, t,r,b,l, r,b,l,t, b,l,t,r},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}

% 1: 45 2: -90 3: -225
% 4: -45 5: -135 6: -270

\newif\ifNEWMANstagger \NEWMANstaggertrue

\def\executechemicalNEWMANSTAGGER%
{\NEWMANstaggertrue\executechemicalNEWMAN}

\def\executechemicalNEWMANECLIPSE%
{\NEWMANstaggerfalse\executechemicalNEWMAN}

\def\executechemicalNEWMAN[#1]%
{\setchemicalname NEWMAN
%
\setchemicalmaximum 6
\setchemicaldistance 0
\setchemicalsubstitute 0
%
\ifNEWMANstagger
\setchemicalrotation 1 0.707 0.707 0.707 -0.707 -0.707 -0.707 -0.707 0.707
\setchemicalrotation 2 0 -1 -1 0 0 1 1 0
\setchemicalrotation 3 -0.707 0.707 0.707 0.707 0.707 -0.707 -0.707 -0.707
\else
\setchemicalrotation 1 .866 -.5 -.5 -.866 -.866 .5 .5 .866
\setchemicalrotation 2 -.259 .966 .966 .259 .259 -.966 -.966 -.259
\setchemicalrotation 3 -.5 -.866 -.866 .5 .5 .866 .866 -.5
\fi
\setchemicalrotation 4 0.707 -0.707 -0.707 -0.707 -0.707 0.707 0.707 0.707
\setchemicalrotation 5 -0.707 -0.707 -0.707 0.707 0.707 0.707 0.707 -0.707
\setchemicalrotation 6 0 1 1 0 0 -1 -1 0
%
\ifNEWMANstagger
\setchemicalangle 1 315 45 135 225
\setchemicalangle 2 90 180 270 0
\setchemicalangle 3 225 315 45 135
\else
\setchemicalangle 1 30 120 210 300
\setchemicalangle 2 255 345 75 165
\setchemicalangle 3 120 210 300 30
\fi
\setchemicalangle 4 45 135 225 315
\setchemicalangle 5 135 225 315 45
\setchemicalangle 6 270 0 90 180
%
\setchemicaltranslate 1 -1500 0
\setchemicaltranslate 2 0 1500
\setchemicaltranslate 3 1500 0
\setchemicaltranslate 4 0 -1500
%
\setchemicallinesegment B1 0 0 1000 0
\setchemicallinesegment B2 0 0 1000 0
\setchemicallinesegment B3 0 0 1000 0
\setchemicallinesegment B4 500 0 1000 0
\setchemicallinesegment B5 500 0 1000 0
\setchemicallinesegment B6 500 0 1000 0
%
\setchemicaltextelement Z 1100 0
%
\setchemicalcircsegment C 0 360 500 360 0 -500
%
\def\processchemical[##1##2##3##4]%
{\processaction
[##1##2##3##4]
[STAGGER????=>{\executechemicalNEWMANSTAGGER[#1]},
ECLIPSE????=>{\executechemicalNEWMANECLIPSE[#1]},
B????=>\processlocalchemicals{B1..6},
CB????=>\processlocalchemicals{B1..6,C,Z1..6},
C????=>\processchemicalcircsegment{C}{1????},
ROT##4=>\processchemicalrotation{##4},
MOV##4=>\processchemicaltranslate{##4},
B##2##3##4=>\processprivatechemicallinesegment{B}{##2##3##4},
Z##2##3##4=>\ifNEWMANstagger
\processchemicaltextelement{Z}{##2##3##4}{#1}{6}
{l,t,r,l,r,b, l,r,l,r,r,l, r,b,l,r,l,t, r,l,r,l,l,r}%
\else
\processchemicaltextelement{Z}{##2##3##4}{#1}{6}
{l,r,t,t,r,b, t,b,r,r,b,l, r,l,b,b,l,t, b,t,l,l,t,r}%
\fi,
\s!unknown=>\unknownchemical{##1##2##3##4}]}}

\def\executechemicalCHAIR[#1]% smaller
{\setchemicalname CHAIR
%
\setchemicalmaximum 6
%
\setchemicallinesegment B1 1600 800 2800 -800
\setchemicallinesegment B2 2800 -800 800 0
\setchemicallinesegment B3 800 0 -1600 -800
\setchemicallinesegment B4 -1600 -800 -2800 800
\setchemicallinesegment B5 -2800 800 -800 0
\setchemicallinesegment B6 -800 0 1600 800
%
\setchemicallinesegment +R1 1600 800 1600 1600
\setchemicallinesegment +R2 2800 -800 2800 -1600
\setchemicallinesegment +R3 800 0 800 800
\setchemicallinesegment +R4 -1600 -800 -1600 -1600
\setchemicallinesegment +R5 -2800 800 -2800 1600
\setchemicallinesegment +R6 -800 0 -800 -800
%
\setchemicallinesegment -R1 1600 800 2350 522 % 750 278
\setchemicallinesegment -R2 2800 -800 3493 -400
\setchemicallinesegment -R3 800 0 1329 -600 % 528 600
\setchemicallinesegment -R4 -1600 -800 -2350 -522 % 750 278
\setchemicallinesegment -R5 -2800 800 -3493 400
\setchemicallinesegment -R6 -800 0 -1329 600 % 528 600
%
\setchemicaltextelement +RZ1 1600 1800
\setchemicaltextelement +RZ2 2800 -1800
\setchemicaltextelement +RZ3 800 1000
\setchemicaltextelement +RZ4 -1600 -1800
\setchemicaltextelement +RZ5 -2800 1800
\setchemicaltextelement +RZ6 -800 -1000
%
\setchemicaltextelement -RZ1 2538 453 % 200 lang
\setchemicaltextelement -RZ2 3666 -300
\setchemicaltextelement -RZ3 1460 -750
\setchemicaltextelement -RZ4 -2538 -453
\setchemicaltextelement -RZ5 -3666 300
\setchemicaltextelement -RZ6 -1460 750
%
\def\processchemical[##1##2##3##4##5]%
{\def\chemicalrotation{1}%
\processaction
[##1##2##3##4##5]
[ B????=>\processlocalchemicals{B1,B2,B3,B4,B5,B6},
-R????=>\processlocalchemicals{-R1,-R2,-R3,-R4,-R5,-R6},
+R????=>\processlocalchemicals{+R1,+R2,+R3,+R4,+R5,+R6},
B##2????=>{\getchemicallinesegment[0][B##2]},
-RZ##4????=>{\getchemicalfixedtextelement[-RZ##4][1][##4][l,l,tc,r,r,bc][#1]},
+RZ##4????=>{\getchemicalfixedtextelement[+RZ##4][1][##4][c][#1]},
-R##3????=>{\getchemicallinesegment[0][-R##3]},
+R##3????=>{\getchemicallinesegment[0][+R##3]},
\s!unknown=>\unknownchemical{##1##2##3##4##5}]}}

\def\executechemicalarrow#1#2[#3]%
{\dogetcommalistelement1\from#3\to\toptext
\dogetcommalistelement2\from#3\to\bottext
\def\dochemicaltext##1%
{\dosetsubscripts%
$\@@dochemicalstyle{\@@localchemicalformat\strut##1}$%
\doresetsubscripts}%
\doifelse\@@chemicallocation\v!intext
{#1{\dochemicaltext\toptext}}%
{\setbox\chemicalsymbols=\hbox
{\box\chemicalsymbols
\vbox{\halign{##\cr
\hbox to 3em{\hss\dochemicaltext{\toptext}\hss}\cr
#2%
\hbox to 3em{\hss\dochemicaltext{\bottext}\hss}\cr}}}}}

\def\executechemicalGIVES
{\executechemicalarrow
{\chemicalsinglepicturearrow}% nodig
{\rightarrowfill\cr}}

\def\executechemicalEQUILIBRIUM
{\executechemicalarrow
{\chemicaldoublepicturearrow}% nodig
{\rightarrowfill\cr\leftarrowfill\cr}}

\def\executechemicalMESOMERIC
{\executechemicalarrow
{\chemicalsinglepicturearrow}% nodig
{$\leftarrow\hskip-1em$\rightarrowfill\cr}}

\def\executechemicalsign#1[#2]%
{\doifelse\@@chemicallocation\v!intext
{\dosetsubscripts
$\@@dochemicalstyle{\@@localchemicalformat#1}$%
\doresetsubscripts}
{\setbox\chemicalsymbols\hbox
{\box\chemicalsymbols
\dosetsubscripts
$\@@dochemicalstyle{\@@localchemicalformat#1}$%
\doresetsubscripts}}}

\def\executechemicalPLUS
{\executechemicalsign{+}}

\def\executechemicalMINUS
{\executechemicalsign{-}}

\def\executechemicalEQUAL
{\executechemicalsign{=}}

\def\executechemicalSPACE[#1]%
{\doifnot\@@chemicallocation\v!intext
{\setbox\chemicalsymbols\hbox
{\box\chemicalsymbols
\quad}}}

\def\executechemicalCHEM[#1]%
{\doifnot\@@chemicallocation\v!intext
{\setbox\chemicalsymbols\hbox
{\box\chemicalsymbols
$\@@dochemicalstyle{\@@localchemicalformat#1}$}}}

\def\executechemicalTEXT[#1]%
{\doifnot\@@chemicallocation\v!intext
{\setbox\chemicalsymbols\hbox
{\box\chemicalsymbols#1}}}

%\def\executechemicalLOW[#1]%
% {\setlowsubscripts}
%
%\def\executechemicalHIGH[#1]%
% {\sethighsubscripts}

\def\putchemicalrule#1#2#3#4%
{\ifcase\chemicaldrawingmode
\putrule from {#1} {#2} to {#3} {#4}
\or
\psline(#1,#2)(#3,#4)%
\or
\bgroup
\!!counta=#1\!!countb=#2\!!countc=#3\!!countd=#4\relax
\global\MPdrawingdonetrue
\setchemicalattributes
\startMPdrawing
x1 := \MPdivten[\the\!!counta]u ;
y1 := \MPdivten[\the\!!countb]u ;
x2 := \MPdivten[\the\!!countc]u ;
y2 := \MPdivten[\the\!!countd]u ;
draw z1--z2 ;
\stopMPdrawing
\egroup
\fi}

\def\executechemicalcomplex#1%
{\bgroup
\putchemicalrule {0} {-\@@chemicalbottom} {0} {\@@chemicaltop}%
\putchemicalrule {0} {\@@chemicaltop} {#1150} {\@@chemicaltop}%
\putchemicalrule {0} {-\@@chemicalbottom} {#1150} {-\@@chemicalbottom}%
\egroup}

\def\executechemicalOPENCOMPLEX[#1]%
{\executechemicalcomplex+\ignorespaces
\executechemicalSPACE[]}

\def\executechemicalCLOSECOMPLEX[#1]%
{\executechemicalSPACE[]%
\executechemicalcomplex-\ignorespaces}

% nog niet door midden as!

\def\executechemicalverticalsymbol#1#2%
{\executechemicalTEXT
[$\left#1\relax
\dimen0=\@@chemicalunit
\scratchcounter=\@@chemicaltop
\advance\scratchcounter by \@@chemicalbottom
\dimen0=\scratchcounter\dimen0
\vcenter to \dimen0{}
\dimen2=\@@chemicalunit
\dimen2=\@@chemicalright\dimen0
\vcenter{\leftskip1em\hsize\dimen2\relax\strut#2\strut}%
\right.$]}%

\def\executechemicalUPARROW[#1]%
{\executechemicalverticalsymbol\uparrow{#1}}

\def\executechemicalDOWNARROW[#1]%
{\executechemicalverticalsymbol\downarrow{#1}}

\def\executechemicalUPDOWNARROW[#1]%
{\executechemicalverticalsymbol\updownarrow{#1}}

\let\setchemicalattributes\relax

\setupchemical
[\c!width=0,
\c!height=0,
\c!left=0,
\c!right=0,
\c!top=0,
\c!bottom=0,
\c!bodyfont=\the\bodyfontsize,
\c!resolution=\outputresolution,
\c!scale=\v!medium,
\c!size=\v!medium,
\c!textsize=\v!big,
\c!frame=\v!off,
\c!axis=\v!off,
\c!state=\v!start,
\c!style=\rm,
\c!location=,
\c!option=,
\c!offset=LOW,
\c!alternative=1,
\c!color=,
\c!rulethickness=,
\c!rulecolor=]

% Tijdelijk plaatsen we deze extra macro's hier.
%
% mathontop: \mtop {} {}
% textontop: \ttop {} {}

\def\putontop#1#2%
{\vbox
{\halign
{\strut\hss##\hss\cr
#1\cr
#2\cr}}}

\def\ttop#1#2%
{\putontop{\tx#1}{#2}}

\def\mtop#1#2%
{\vbox
{\offinterlineskip
\halign
{\hss##\hss\cr
$\scriptscriptstyle#1$\cr
\noalign{\vskip.5ex}%
$#2$\cr}}}

\def\ctop#1#2%
{\vbox
{\offinterlineskip
\halign
{\hss##\hss\cr
$\@@dochemicalstyle{\@@localchemicalformat\scriptscriptstyle#1}$\cr
\noalign{\vskip.5ex}%
$\@@dochemicalstyle{\@@localchemicalformat#2}$\cr}}}

%D Here are a couple of \CONTEXT\ goodies:
%D
%D \startitemize
%D \item styles hooked into \CONTEXT\ style mechanism
%D \item support for color and rulethickness (mp mode only)
%D \item position tracking
%D \stopopsoming

\ifCONTEXT \else \protect \endinput \fi

\def\setchemicalattributes
{\scratchdimen\@@chemicalchemicalrulethickness
\def\chemicalattributes
{withpen pencircle scaled \the\scratchdimen\space
withcolor }%
\doifelsenothing\@@chemicalchemicalrulecolor
{\edef\chemicalattributes{\chemicalattributes black}}
{\edef\chemicalattributes
{\chemicalattributes \MPcolor{\@@chemicalchemicalrulecolor}}}%
\startMPdrawing
drawoptions (\chemicalattributes) ;
\stopMPdrawing}

\let\@@chemicalcolor\empty

\def\@@dochemicalcolor
{\doifsomething\@@chemicalcolor{\color[\@@chemicalcolor]}}

\def\@@dochemicalstyle
{\doconvertfont\@@chemicalstyle}

\setupchemical
[\c!rulethickness=\linewidth,
\c!rulecolor=,
\c!color=]

\def\cpos#1#2%
{\iftrialtypesetting
#2%
\else
\bgroup
\globalpushmacro\dowithchemical
\gdef\dowithchemical##1{\hpos{#1}{##1}\globalpopmacro\dowithchemical}%
#2%
\egroup
\fi}

\protect \endinput