BOND REACTIVITIES, ACIDITIES, AND BASICITIES WITHIN AMO3X3 PHASES (A = LI, NA, K, IN X = SE, TE)

In order to explain the varying solubility of AMo3X3 phases (A = Li, Na, K, In; X = Se, Te) in polar solvents, we investigate theoretically the chemical character of Mo-Mo, Mo-X, and A-X bonds. The computation of both bond energies as well as the newly defined increments of reactivity, electrophilicity, and nucleophilicity (inspired by a density-functional formalism suggested by Parr and Pearson) reveals that (i) Mo-Mo bonds are chemically inert, (ii) the dissolution of Li- and Na-containing phases is due to the high acidity of A-X bonds, easily attacked by Lewis bases, and (iii) the Mo-X bonds show high basicity throughout the whole series of compounds. The latter finding gives rise to the assumption that strong Lewis acids will seek out Mo-X bonds as "targets" in liquid-state solid-state acid-base reactions.