The bonding in the halogen polyfluorides is similar to that in the xenon fluorides. Since XeF(4) exists, the previously unreported ClF(5) should exist. This compound has been prepared by heating ClF(3) in the presence of fluorine at high pressure. Chlorine pentafluoride is a square pyramidal molecule. It has a lower melting point than ClF(3) and a higher vapor pressure. It is also less reactive than ClF(3).