Dear list, According to the information on contextgarden (section chemistry) chemical reactions should be entered as follows: \usemodule[chemic] \startformula \chemical{CaCO_3(s),+,HCl(g),->,CaCl(HCO_3)(s)} \stopformula That produces a formula with the comma's in it, so that's not good. If I enter it as follows \usemodule[chemic] \startformula \chemical{CaCO_3(s) + HCl(g) \rightarrow CaCl(HCO_3)(s)} \stopformula Then somehow after the \rightarrow the math/chemical environment is lost and the remainder gets typeset as text. The same is true if I use any math command such as \beta or \cdot. The closest I get to the desired result is with the following: \usemodule[chemic] \startformula \chemical{CaCO_3(s) + HCl(g) --> CaCl(HCO_3)(s)} \stopformula But that is a bit of a compromise. Regards, David van Diepen