Thermochemical properties (D-o(o) and IP) of the lanthanide monohalides

Thermochemical data for the lanthanide monohalides have been combined with recent ligand field theory calculations (A. L. Kaledin, M. C. Heaven, R. W. Field, and L. A. Kaledin (1996). J. Mel. Spectrosc. 179, 310) to estimate the dissociation energies and ionization potentials for all LnX (where Ln i s an element of Ba through Lu, and X is an element of F, CI, Br, or I) mole cules and the dissociation energies for the LnX(+) ions. Owing to the negli gible involvement of the core-like 4f electrons in bonding, the dissociatio n energies and ionization potentials of all LnX molecules, where Ln is an e lement of Ba through Lu, and X is an element of O, S, F, CI, Br, or I, shou ld vary with Ln atom in a simple linear manner, provided that corrections a re made for differences in S-orbital occupancy between the LnX molecule and the free Ln atom or between the LnX molecule and the LnX+ molecular ion. W e provide such a model here and, in so doing, correct several inconsistenci es in the thermochemical data. Based on thermochemical data (A. A. Kitaev, I. S. Gotkis, P. G. Val'kov, and K. C. Krasnov (1996). Russ. Chem. Phys. 7, 1685) and recent spectroscopic observations (M. C. McCarthy, J. C. Bloch, R. W. Field, and L. A. Kaledin (1996) J. Mel. Spectrosc. 179, 251), a revis ed Value for the ionization potential of DyF, IP(DyF) = 5.85 +/- 0.06 eV, i s proposed. (C) 1999 Academic Press.