Published online by Cambridge University Press: 25 May 2016
We review the properties of hot molecular cores with specific reference to chemical modelling. While most theoretical modelling has been generic, we discuss models for two specific sources, G34.3+0.15 and W3 (H2O). We show that the hot core gas in both these regions has an age of 5 103 — 104 yrs and that the abundances of many molecules are consistent with formation in the gas-phase following evaporation of simple molecular ices from the grains. We end with a discussion of current problems and future directions.