%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 8-2-40 on page 540.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{207.83385pt}

\StartShownPreambleCommands
\usepackage{xymtexps,chmst-ps}
\StopShownPreambleCommands
\begin{document}
\begin{chemeqn}
HO\sp{-}~+~
\raisebox{-28pt}{\ltetrahedralS{0==C;1==Cl;%
                                2==C$\sb{3}$H$\sb{7}$;%
                                3A==CH$\sb{3}$;4B==C$\sb{2}$H$\sb{5}$}}
\reactrarrow{0pt}{1cm}{}{}\qquad
\raisebox{-28pt}{\dtrigpyramid[{0{~~$\delta+$}}]%
                              {0==C;4A==HO$\sp{\delta-}$;%
                               5A==Cl$\sp{\delta-}$;%
                               1==C$\sb{3}$H$\sb{7}$;%
                               2A==CH$\sb{3}$;%
                               3B==C$\sb{2}$H$\sb{5}$}}
\quad\reactrarrow{0pt}{1cm}{}{}\quad
\raisebox{-28pt}{\rtetrahedralS{0==C;1==HO;%
                                2==C$\sb{3}$H$\sb{7}$;%
                                3A==CH$\sb{3}$;4B==C$\sb{2}$H$\sb{5}$}}
~+~Cl\sp{-} \label{myeqn}
\end{chemeqn}
\end{document}