POLYHEDRAL BORON-NITRIDE MOLECULES

The geometrical and electronic structures of two isomers (1 and 2) of the polyhedral boron nitride molecule, B12N12, have been calculated us ing the MNDO method. Structure 1 having the form of a truncated octahe dron is more energetically preferable (DELTAH0f = -128 kcal mol-1) tha n isomer 2, which has C6v symmetry. The equilibrium geometries of the N6B6(CH2)6 isomers (3 and 4), which simulate fragments of structure 2, have been calculated. The stabilization mechanism of the N6 nitrogen cluster (hexaazabenzene) in polyhedral structures is discussed. The pa rameters calculated for molecules 1 and 2 have been correlated with th e corresponding characteristics of their carbon analogs.