As we'll be seeing a lot of chemical formulae, and since mathjax is available, we should define a standard way of representing chemical formulae in our posts.

I propose something like \mathrm{formula} as in


which is neat. Anybody feel fancier?

We also need to figure out how to write chemical names. What do you think of something like \textbf{chemical} as in

$\textbf{diketone}$ ?


After writing a question using \textbf{} to wrap chemical names, I think that using the standard markdown **text** while using \mathrm{} for formulae command looks better.

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    $\begingroup$ I've filed a request for mhchem on the main meta… $\endgroup$ – F'x Apr 26 '12 at 16:26

Mathjax 2.0 supports the mhchem extension with stuff like \ce{H2O} etc. Either we bug the SE overlords to upgrade us, or we just copy the formatting of mhchem.

In the meantime, we can use the \require{} mathjax extension enabling switch. Eg:

 $\ce{HCl}$ dissociates in water as follows:
 $$\ce{H2O +HCl<=>H3O+ +Cl-}$$

Which yields:

formula rendering

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  • $\begingroup$ SE is already using MathJax 2.0 as far as I know, it's only a matter of enabling this specific module. $\endgroup$ – Mad Scientist Apr 26 '12 at 5:45

I agree with Nick T that particularly $\mathrm{}$ looks so different from the surrounding text that it becomes hard to read: the combination of the large size and roman font is ok for mathematics where most letters are lowercase and italicised, but not for bulky chemical formulas. That's why I'd prefer $\mathsf{}$ as I used here, but it still looks a bit out of place. It also needs $\small$ added, because the letters are to tall otherwise. At any rate, I think one should use a unified $\newcommand{}$ at the beginning for plain-MathJax solutions.

Directly using html tags yields of course the most native look, but is IMO unacceptable because it's really awkward to type. I'd rather use Unicode characters then, like

H₂SO₄ + H₂O  ⇌  HSO₄⁻ + H₃O⁺

Both have an improvised, unprofessional feel about them and lack proper environments for e.g. aligned equations.

mhchem with suitable settings would definitely be the best solution.

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If I'm only throwing out a couple formulae, especially inline with text, I somewhat prefer using <sup> and <sub> as it just looks better and doesn't have some jarring transition.


CO32− compounds or simply CO2 dissolved in water makes my enzyme work.

CO<sub>3</sub><sup>2&minus;</sup> compounds or simply CO<sub>2</sub> [...]
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  • $\begingroup$ Or using equivalent LaTex notation. $\endgroup$ – Khaloymes Apr 26 '12 at 15:27
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    $\begingroup$ @Khaloymes my point was that the LaTeX doesn't fit well with the rest of the text, and if using a couple formulae it sticks out like a sore thumb, (e.g. here) $\endgroup$ – Nick T Apr 26 '12 at 17:47

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