Dissociation Energies of Diatomic Molecules of the Transition Elements. I. Nickel

Abstract

The Ni₂ molecule has been shown to exist in the vapor phase over liquid nickel above 2000°K. Using information derived from a combination of effusion and mass‐spectrometric techniques, the dissociation energy of Ni₂ has been calculated from the ratio of dimeric and monomeric nickel in equilibrium with liquid: D₀⁰(Ni) = 54.5±5 kcal. From the accepted value of the heat of sublimation of nickel and the dissociation energy of the dimer the heat of sublimation for the process 2Ni(solid) = Ni₂(gas) is, at 0°K, 146.9±7 kcal.