## LaTeX forum ⇒ Math & Science ⇒ Arrow for multiple consecutive reactions

Information and discussion about LaTeX's math and science related features (e.g. formulas, graphs).
Sonntag
Posts: 13
Joined: Sun May 24, 2015 3:37 pm

### Arrow for multiple consecutive reactions

Hi!

There's a possibility to get an arrow like on the attached graphic?

Sonntag
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Johannes_B
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TikZ; used by chemmacros, chemexec and mhchem; has an own arrow-library. It is likely that this kind of arrow is included. Unfortunately, the documentation is quite big and intimidating and always slowing down my machine to an almost standstill.
The smart way: Calm down and take a deep breath, read posts and provided links attentively, try to understand and ask if necessary.

Sonntag
Posts: 13
Joined: Sun May 24, 2015 3:37 pm
Thank you! Went through them but couldn't find any arrow like that yet.

Johannes_B
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In your picture are two very simple arrows. Or are you referring to the unit of both as an arrow?

Can you give examples and references where this is used? If this is a sensible issue, i am sure Clemens will add this to chemformula.
The smart way: Calm down and take a deep breath, read posts and provided links attentively, try to understand and ask if necessary.

Sonntag
Posts: 13
Joined: Sun May 24, 2015 3:37 pm
I refer to the unit.

It is an abbreviation that you use if you skip reaction steps to get to the written products (outgoing from the written educts.)

Johannes_B
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Please add some references where this is actually used. I am not a chemist, i have seen this here for the first time. In order to make a feature request, we need some backup.

Since my Tikz-foo is very very limited, i could only come up with the following.
\listfiles\documentclass{article}\usepackage{chemmacros}\ExplSyntaxOn\NewChemArrow { =>>> }{	\draw[chemarrow,-cf]	([yshift=.15ex]cf_arrow_start) -- ([yshift=.15ex]cf_arrow_end) ;	\draw[chemarrow,-cf]	([yshift=-.35ex,xshift=.7em]cf_arrow_start) -- ([yshift=-.35ex,xshift=.7em]cf_arrow_end) ;}\ExplSyntaxOff\begin{document}\begin{reaction}	a =>>> D\end{reaction}\end{document}
The smart way: Calm down and take a deep breath, read posts and provided links attentively, try to understand and ask if necessary.

cgnieder
Site Moderator
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chemformula and its \NewChemArrow is the right choice here, IMHO. I am reluctant to add this arrow to chemformula but the command \NewChemArrow is provided for exactly such purposes.

There is no need for \ExplSyntaxOn in order to use it, by the way.

Personally I'd set the arrows a little bit closer to each other but that is probably a matter of personal taste…

\documentclass{article}\usepackage{chemformula} \NewChemArrow{>>}{   \draw[chemarrow,-cf]     ([yshift=.2ex]cf_arrow_start) -- ([yshift=.2ex]cf_arrow_end) ;   \draw[chemarrow,-cf,]     ([yshift=-.2ex,xshift=.3em]cf_arrow_start) -- ([yshift=-.2ex,xshift=.3em]cf_arrow_end) ;} \begin{document} \ch{A >> B >>[above][below] C} \end{document}

chemarrow.png (14.09 KiB) Viewed 3706 times
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Sonntag
Posts: 13
Joined: Sun May 24, 2015 3:37 pm
Thank you!