# Correctly placing the benzene ring in Polystyrene

First post, sorry if I get the formatting wrong. I am attempting to produce a Display Formula for Poly Styrene, but have not been able to get the benzene ring to place properly. This is my current attempt:

I want to create a Benzene ring with Carbon atoms placed at the six nodes of the ring. I am using chemfig package to achieve this. But it so happens that the bond is actually going into the Carbon atom at one of the sites.

MWE and is appended below. Along with the desired output

\documentclass{article}
\usepackage{chemfig}

\begin{document}

\chemfig{-[@{op,.5}]C(-[2]([:-30]*6(=-=-=-)))(-[6]H)-C(-[2]H)(-[6]H)-[@{cl,.5}]}

\end{document}


• Welcome to TeX.SX! It is actually a good first post :) – TeXnician Oct 27 '18 at 11:40
• @Fran I think the picture signals the requested output (as stated now)(en.wikipedia.org/wiki/Polystyrene) and OP gets something different. – albert Oct 27 '18 at 12:35
• @Albert Now I see it. I will delete the comment. Thanks – Fran Oct 28 '18 at 7:17

You should write with the code setpolymerdelim in the chemfig manual

\documentclass{article}
\usepackage{chemfig}

\begin{document}
\newcommand\setpolymerdelim[2]{\def\delimleft{#1}\def\delimright{#2}}
\def\makebraces[#1,#2]#3#4#5{%
\edef\delimhalfdim{\the\dimexpr(#1+#2)/2}%
\edef\delimvshift{\the\dimexpr(#1-#2)/2}%
\chemmove{%
\node[at=(#4),yshift=(\delimvshift)]
{$\left\delimleft\vrule height\delimhalfdim depth\delimhalfdim width0pt\right.$};%
\node[at=(#5),yshift=(\delimvshift)]
{$\left.\vrule height\delimhalfdim depth\delimhalfdim width0pt\right\delimright_{\rlap{$\scriptstyle#3$}}$};}}
\setpolymerdelim[]
\chemfig{-[@{left,0.3},1.5]C(-[:90]*6(=-=-=-))(-[6]H)-C(-[2]H)(-[6]H)-[@{right,0.8}]}
\makebraces[90pt,30pt]{n}{left}{right}
\end{document}

• Thank you very much; don't think I would have got there myself any time soon. – Hugo F Oct 27 '18 at 13:13
• @HugoF if GézàLaTeX's answer has solved your problem, the usage is to accept it, read : tex.stackexchange.com/help/someone-answers – AndréC Oct 27 '18 at 13:36
• I think it would be fair to mention that the entire code chunk for \setpolymerdelim (lines 5 to 16) is taken from the chemfig manual, section 12.4 Draw a ploymer element (p. 43). And yes, currently there is a typo in the section title so it's tricky to find the answer by searching the manual:) – andselisk Oct 27 '18 at 15:10