[XeTeX] Need some input about \newcommand to create alias

[Wilfred van Rooijen]

An even better solution:

\usepackage[version=3]{mhchem}

Then simply type \ce{CO2} :-))

The package mhchem is one of the most helpful packages for chemistry-related typesetting. If you do a lot of scientific typesetting, also see the SIunits package - it is fantastic!

Wilfred

PS your solution of \codeux or similar is deficient in the sense that it uses a math environment to set the '2', which may cause strange spacing (characters are not spaced in the usual way in a math environment. To see what I mean, type eff and $eff$ and observe the ugly result). Also the math environment may use a different font from the normal text, so that the '2' would look different from for instance the page number. It depends on taste whether you want that or not. A better option would be to use CO$_\text{2}$, or maybe CO$_\mathrm{2}$. The mhchem package does something similar, but also has an automatic detection, so that you can type \ce{C2H5OH} and get what you want.



--- On Sat, 28/11/09, Alan Munn <amunn at msu.edu> wrote:

> From: Alan Munn <amunn at msu.edu>
> Subject: Re: [XeTeX] Need some input about \newcommand to create alias
> To: "Unicode-based TeX for Mac OS X and other platforms" <xetex at tug.org>
> Date: Saturday, 28 November, 2009, 1:38 PM
> At 11:23 PM -0500 11/27/09, Maxim
> Cournoyer wrote:
> > Dear XeTeX fidels,
> > 
> > In my first document written with XeTeX, I wanted to
> do an alias for the abbreviation CO_2 (carbon dioxyde), but
> had two difficulties.
> > 
> > My first one was to try to use something like this :
> %\newcommand{\co2}{CO$_2$}
> > The problem was that it seems we cannot use "numbers"
> in the command name, such as the '2' in \co2. Is there a way
> to circumvent this?
> 
> Not really. Numbers aren't allowed in macro names.
> 
> > 
> > Another weird issue I ran into was, after
> changing  \co2 to something more wordy as \codeux, my
> actual replacement would delete all trailing space. Let me
> explain by an example :
> > ex : The traffic in developed nations  is the
> cause to an average of 26% of t
sults : The traffic in developed nations  is
> the cause to an average of 26% of the CO_2emissions.
> > 
> > Note the lack of a space character between the _2
> subscript and emissions. Using CO$_2$ straight in my text
> solved the problem, surprisingly. Is there an explanation
> for this?
> 
> Yes, commands gobble the spaces after them.
> 
> >  What should I do to prevent this from
> happening?
> 
> Two solutions:
> 
> \newcommand{codeux}{CO$_2${}}
> 
> or
> 
> \usepackage{xspace}
> \newcommand{codeux}{CO$_2$\xspace}
> 
> 
> Alan
> 
> P.S. Neither of these questions is actually related to
> xetex.  You might want to check the TeX FAQ, and get a
> good introduction to LaTeX.  Or post your questions to
> the comp.text.tex newsgroup.
> 
> http://www.tex.ac.uk/cgi-bin/texfaq2html?introduction=yes
> 
> 
> -- Alan Munn       
>            
>     amunn at msu.edu
> Department of Linguistics
> and Germanic, Slavic, Asian and African
> Languages        Tel.
>     517-355-7491
> Michigan State University, East Lansing MI 48824
> USA    Fax    517-432-2736
> 


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