Chlorine pentafluoride

Chlorine pentafluoride has formula ClF5. It was first synthesized in 1963.

Its square pyramidal structure with C4v symmetry was confirmed by its high resolution19F NMR spectrum.

Preparation
Initially, a common method for synthesis of this hypervalent molecule was to react ClF3 with F2 at high temperatures and high pressures. Also, reacting metal fluorides, MClF4 (i.e. KClF4, RbClF4, CsClF4) with F2 produced ClF5 and the corresponding MF. In 1981, researchers found that NiF2 is an excellent catalyst for generating ClF5.

Reactions
ClF5 reacts readily with water to produce FClO4 and HF. It also a strong fluorinating agent. While unreactive with first row nonmetals, it reacts readily with second and third row nonmetals at room temperature.