THEORETICAL-STUDIES OF STRUCTURE, STABILITY, AND CHEMICAL BONDING IN OXOHYDRIDE OM(4)H(6) COMPLEXES

The results of ab initio RHF/3-21G, RHF/6-31G, and MP2/6-31G**//HF/6- 31G calculations for 10 possible configurations of OM(4)H(6) molecule s (MO . 3MH(2), M = Be, Mg) are reported. Five isomers of OBe4H6 and t hree isomers of OMg4H6 have been found within an energy range of simil ar to 15 kcal mol(-1). The ''lanternlike'' C-3v structure is the most favorable one for both complexes. Both molecules OM(4)H(6) are stable to decomposition through all of the studied pathways. Chemical bonding in the OM(k) polyhedra containing two-, three- and four-coordinated o xygen atoms is discussed. (C) 1996 John Wiley & Sons, Inc.