Mass-Spectrometric Determination of the Dissociation Energies of the Gaseous CuNi, CuCo, and CuCr

The molecules CuX (X=Ni, Cu, and Cr) have been shown to exist in the vapor phase over liquid solutions of copper and the transition metals at high temperatures (1550–2000°K). Using information derived from a combination of effusion and mass-spectrometer techniques, the equilibrium constants and energetics of the reactions CuX+Cu=Cu2+X have been determined. The dissociation energies as obtained by the second-law method are 47.4 ± 5, 38.0 ± 5, and 36.0 ± 6 kcal mole−1 for CuNi, CuCo, and CuCr, respectively.