[dī¦klȯr·ō¦flu̇r·ō′me‚thān] (organic chemistry) CHCl2F A colorless, heavy gas with a boiling point of 8.9°C and a freezing point of -135°C; soluble in alcohol and ether; used in fire extinguishers and as a solvent, refrigerant, and aerosol propellant. Also known as fluorocarbon 21; fluorodichloromethane.