# chemfig: how to align the arrows of different schemes?

I am trying to get the arrows of three different schemes aligned but would like to have text in between them, as you can see below.

Despite searching for hours, i haven't found a solution..

\documentclass[a4paper,pdftex,ngerman,12pt]{article}
\usepackage{chemfig}
\setatomsep{1.5em}
\setcrambond{1.5ex}{1pt}{2pt}

\begin{document}
\noindent \textbf{Cracken von Seitenketten in Aromaten:}

\schemestart
\chemfig{**6([:-150]-----(-C_4H_9)-)}
\arrow
\chemfig{**6([:-150]-----(-C_2H_5)-)} \arrow{0}[,0]\+ \chemfig{H_2C=CH_2}
\schemestop
\newline\newline

\noindent \textbf{Dealkylierung:}

\schemestart
\chemfig{**6([:-150]-----(-C_2H_5)-)}
\arrow
\chemfig{**6([:-150]------)}\arrow{0}[,0] \+ \chemfig{H_2C=CH_2}
\schemestop
\newline\newline

\noindent \textbf{Cracken von Olefinen:}
\newline

\schemestart
\chemfig{CH_3-[:150]-[:-150]-[:150]-[:-150]=[:150]-[:-150]H_3C}
\arrow
\chemfig{CH_3-[:-150]=[:150]-[:-150]H_3C} \arrow{0}[,0]\+ \chemfig{CH_3-[:150]=[:-150]H_3C}
\schemestop
\end{document}


• is this altogether supposed to be one figure (with a common caption) or rather part of running text like several math equations? Nov 1, 2015 at 16:35
• I would rather have it as a part of a running text, because i would like to add text below the headings. If its only possible as one figure, that would be fine, too. Nov 2, 2015 at 18:33

I'm sure there is a more elegant way, but a crude approach is to calculate the difference in width between each of the smaller left compounds (the first two) and the largest (the last) and add that as \hspace before the start of the smaller reactions. Showing each step:

\documentclass[a4paper,pdftex,ngerman,12pt]{article}
\usepackage{chemfig}
\setatomsep{1.5em}
\setcrambond{1.5ex}{1pt}{2pt}

\begin{document}
%Width of first
\newlength\lenfirst
\settowidth\lenfirst{\chemfig{**6([:-150]-----(-C_4H_9)-)}}
%Width of second
\newlength\lensecond
\settowidth\lensecond{\chemfig{**6([:-150]-----(-C_2H_5)-)}}
%Width of third
\newlength\lenthird
\settowidth\lenthird{\chemfig{CH_3-[:150]-[:-150]-[:150]-[:-150]=[:150]-[:-150]H_3C}}

%Difference for first
\newlength\lendelfirst
\setlength\lendelfirst{\lenthird}

%Difference for the second
\newlength\lendelsecond
\setlength\lendelsecond{\lenthird}

\noindent \textbf{Cracken von Seitenketten in Aromaten:}

\hspace{\lendelfirst}\schemestart
\chemfig{**6([:-150]-----(-C_4H_9)-)}
\arrow
\chemfig{**6([:-150]-----(-C_2H_5)-)} \arrow{0}[,0]\+ \chemfig{H_2C=CH_2}
\schemestop
\newline\newline

\noindent \textbf{Dealkylierung:}

\hspace{\lendelsecond}\schemestart
\chemfig{**6([:-150]-----(-C_2H_5)-)}
\arrow
\chemfig{**6([:-150]------)}\arrow{0}[,0] \+ \chemfig{H_2C=CH_2}
\schemestop
\newline\newline

\noindent \textbf{Cracken von Olefinen:}
\newline

\hspace{0pt}\schemestart
\chemfig{CH_3-[:150]-[:-150]-[:150]-[:-150]=[:150]-[:-150]H_3C}
\arrow
\chemfig{CH_3-[:-150]=[:150]-[:-150]H_3C} \arrow{0}[,0]\+ \chemfig{CH_3-[:150]=[:-150]H_3C}
\schemestop
\end{document}