Fluorination of Some Group IX and X Metals and Their Lower Fluorides by Monofluorine and Difluorine Mixtures

The fluorination of metallic platinum and of cobalt(II) and nickel(II) fluorides with nonequilibrium mixtures of F 2 containing high percentages of F is considered in terms of the acquisition of thermodynamic equilibrium. The enthalpy of the reaction Ni 2 F 5 (cr) = 2NiF 2 (cr) + 1/2F 2 (g) was determined by an independent method to be Δ r H °(0) = –59.9 ± 1.5 kJ/mol, and the enthalpy of formation was verified: Δ f H °(Ni 2 F 5 (cr), 0 K). A correlation was shown between the experimentally determined sequences of reactions that occur inside a nickel effusion cell and their enthalpies.