Isoflurane is a volatile, non-flammable, non-explosive, clear, colourless, stable liquid, with a mildly pungent, musty ethereal odour. Chemically, it is 1-chloro-2, 2, 2-trifluoroethyl difluoromethyl ether. It has a purity greater than 99.9% and contains no additives or chemical stabiliser.