[Tex/LaTex] Define ring bond length in chemfig

chemfig

How can one define the bond length for a ring system in chemfig? **6(-[,0.5]-[,0.5]-[,0.5]-[,0.5]-[,0.5]-[,0.5]) does not work, sadly.

EDIT:

The answer provided resizes the ring system, but not the circle within it, on my system. Here's my configuration:

\documentclass[11pt]{amsart}
\usepackage[landscape, top=0.3cm, left=0.1cm, right=0.3cm, bottom=0.3cm]{geometry}                % See geometry.pdf to learn the layout options. There are lots.
\geometry{letterpaper}                   % ... or a4paper or a5paper or ... 
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{epstopdf}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[version=3]{mhchem}
\usepackage{chemfig, chemmacros}
\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}

\begin{document}

Best Answer

You can set the bond length at the begining of the ring:

\chemfig{A-*6([,0.5]------)}

gives a ring with half lengthed bonds.

EDIT: this work also with **n syntax. For example

\chemfig{A-**6([,0.5]------)} \chemfig{A-**6(------)}

gives

enter image description here

Related Solutions

[Tex/LaTex] How to selectively change bond length in chemfig

Chemfig's bonds have an optional argument that takes several parameters one of them being a factor to scale the bond length:

<bond>[<angle spec>,<length factor>,<other parameters>]

So you can just add that option to the bonds you want shorter:

\documentclass[a4paper,11pt]{scrartcl}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{chemfig}

\begin{document}

\setatomsep{50pt}
\chemfig{
  CH
   (-O-[:30]C(=[:90,.7]O)-[:-30]R_2)
   (-[:90]CH_2-O-[:30]C(=[:90,.7]O)-[:-30]R_1)
   (-[:-90]CH_2-O-[:30]C(=[:90,.7]O)-[:-30]R_3)
}

\end{document}

enter image description here

[Tex/LaTex] How to alter the bond length of a double bond in chemfig

I defined TikZ decorations:

\documentclass{article}
\usepackage{chemfig}
\usetikzlibrary{decorations}
\makeatletter
\newdimen\mystartshorten
\newdimen\myendshorten
\mystartshorten0pt
\myendshorten0pt
\pgfdeclaredecoration{sdbond}{initial}{
  \state{initial}[width=\pgfdecoratedremainingdistance,next state=final]
  {
    {
      \pgftransformyshift{\CF@double@sep}
      \pgfpathmoveto{\pgfqpoint{\mystartshorten}{0pt}}
      {
        \pgftransformxshift{\pgfdecoratedremainingdistance}
        \pgfpathlineto{\pgfqpoint{-\myendshorten}{0pt}}
      }
    }
    \pgfpathmoveto{\pgfpointorigin}
    \pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{0pt}}
  }
  \state{final}
  {}
}
\tikzset{
  lsdbond/.code 2 args={%
    \tikzset{decorate, decoration=sdbond}%
    \pgfmathsetlength\mystartshorten{\CF@double@sep*cot((#1)/2)}%
    \pgfmathsetlength\myendshorten{\CF@double@sep*cot((#2)/2}%
  },
  rsdbond/.code 2 args={%
    \tikzset{decorate, decoration={sdbond, mirror}}%
    \pgfmathsetlength\mystartshorten{\CF@double@sep*cot((#1)/2)}%
    \pgfmathsetlength\myendshorten{\CF@double@sep*cot((#2)/2}%
  }
}
\setdoublesep{0.4em}
\setatomsep{2em}
\makeatother
\begin{document}
\chemfig{[:60]--[::-60,,,,,rsdbond={120}{120}]-[::-60]}
\chemfig{[:90]--[::-90,,,,,rsdbond={90}{60}]-[::-120]}
\end{document}

Two decorations lsdbond (left short double bond) and rsdbond (right short double bond) are defined. lsdbond puts the shortened (pi) bond on the left of the middle (sigma) bond, and rsdbond on the right. They take two arguments: the first is the bond angle on the departure atom of the bond; the second on the arrival atom. The angles are in degrees and should be in the range of (0,180].

Best Answer

Related Solutions

[Tex/LaTex] How to selectively change bond length in chemfig

[Tex/LaTex] How to alter the bond length of a double bond in chemfig

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