# How do we write catalysis when writing equations?

Many reactions are invoked/sped up by presence of certain chemical substance. This is called catalysis.

As far as I know, catalyst is then written above the arrow of the reaction. The same is also used when reaction requires certain temperature or pressure. How do I write this properly using Tex?

So far, was using this approach:

$$\ce{2NaHCO3 →300°C→ Na2CO3 + H2O + CO2}$$

I don't really like it.

• I just noticed you use unicode → to set the arrows. There are a variety of possibilities to do that with mhchem which is implemented in MathJax. For example $\ce{->}$ $\ce{->}$; $\ce{<->}$ $\ce{<->}$; $\ce{<=>}$ $\ce{<=>}$, $\ce{<<=>}$ $\ce{<<=>}$ ... Use the sandbox to experiment :D – Martin - マーチン Jul 8 '14 at 7:09

Use [...] right after the arrow. Use it again if you want to add more text below the arrow. $$\ce{Pb ->[\rm magic][\Delta] Au}$$
If you want to include chemical formulas you have to include them in [\ce{...}]$$\ce{Pb ->[\mathrm{magic}~\ce{H2O}][\Delta] Au}$$
Use T[...] right after the arrow to add descriptive text. If you want to add something below the equation, this will also be set as text, you have to escape with $...$ again if you want to add math or chemistry $\ce{...}$. $$\ce{Pb ->T[magic water with the eye of Newt][\Delta] Au}$$
• I also noticed you used a TeX style command \rm, while here this does not really matter, but in a LaTeX document this might destroy your markup. Use {\rmfamily ...}, \textrm{}, \mathrm{} instead. – Martin - マーチン Jul 8 '14 at 7:18