1,151,665. Unsaturated fluorocarbonyl compounds. ALLIED CHEMICAL CORP. 8 Dec., 1967 [8 Dec., 1966], No. 55961/67. Heading C2C. The compound of general formula wherein each of X and Y which may be the same or different represents a fluorine or chlorine atom, and A represents a fluorine atom or a radical having the formula -OR, wherein R represents a hydrogen atom, or an unsubstituted or halogen-substituted alkyl, cycloalkyl. aryl, alkaryl or aralkyl radical, is made by heating a 2,2 - bis - (fluoroperhalomethyl)- 3,4 - difluorooxetene of the general formula to a temperature of between 40‹ and 140‹ C., in the presence of a chemical or radiant energy free radical initiator, and in the presence or absence of a solvent. In all the examples iodine is used as initiator with an ether as solvent.