Nickel fluoride

Nickel(II) fluoride is the chemical compound with the formula NiF2. Its is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air. Nickel(II) fluoride is the chemical compound with the formula NiF2. Its is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air. NiF2 comprises the passivating surface that forms on nickel alloys (e.g. monel) in the presence of hydrogen fluoride or elemental fluorine, which is why nickel and its alloys are among the few materials that can be used to store or transport these fluorine compounds. NiF2 is also used as a catalyst for the synthesis of chlorine pentafluoride. NiF2 is prepared by treatment of anhydrous nickel(II) chloride with fluorine at 350 °C: The corresponding reaction of cobalt(II) chloride results in oxidation of the cobalt, whereas nickel remains in the +2 oxidation state after fluorination because its +3 oxidation state is less stable. Chloride is more easily oxidized than nickel(II). This is a typical halogen displacement reaction, where a halogen plus a less active halide makes the less active halogen and the more active halide.