I would need to typeset some rather simple reaction equations. I do not need the structural capabilities of PPCHTeX, just something simpler. The thing I am writing has something to do with physical chemistry, so I need mathematical equations, as well. Of course, the natural way to do this: \placeformula \startformula \rm NH_3(g) + H^+(aq.) + Cl^-(aq.) \rightarrow NH_4^+(aq.) + Cl^-(aq.) \stopformula This gives rather pleasant-looking results. However, is this the right (i.e. kosher) way of doing things, or do I run into trouble at some later point with this? What are you chemists using? And how do I switch off the equation numbering for the chemical reactions (I'd like to have the mathematical formulae still numbered)? TIA, - Ville