“…In the study of the polymerization of acenaphthene at high temperatures (45), a very high-melting crystalline compound, CísHís, was obtained in 4-5 per cent yield. The material, fluorocyclene, was considered to have one of the two following structures: Subsequent work (44,46,47) showed that fluorocyclene can be produced in yields of 25-38 per cent when the acenaphthene is heated at high temperatures in the presence of lead oxides.…”