Dissociation Energy of Copper Monofluoride

Abstract

High‐temperature gaseous equilibria in the Mg–Cu–F system were studied by mass spectrometry and the results were used to derive the dissociation energy of CuF. For the reaction MgF(g) + Cu(g) = Mg(g) + CuF(g), ΔH 298 = 7.1 ± 2 kcal , leading to D° 298 (CuF) = 103 ± 2.2 kcal (4.47 eV ) . This result differs from those obtained on many other mono‐ and difluoride combinations in that D(Cu–F) > D(CuF–F) . It can be shown, however, that this reversal of bond strengths in the Cu–F system is consistent with the valence‐state concept of bonding.