STRUCTURE AND STABILITIES OF (HA1NH)(N) (N = 2-4)

Ab initio molecular electronic structure methods have been used to stu dy the relative stability of the planar inorganic ring (HAlNH)(n) (n = 2-4) during homodesmotic and monomer polymerization reactions. Optimi zed geometries, frequencies and energies through restricted Hartree-Fo ck/6-31G are reported, and energies at the self-consistent field opti mized geometries including Moller-Plesset fourth perturbation theory w ith single, double and quadruple excitation (MP4SDQ) corrections are a lso reported for both reactions. Homodesmotic reactions with MP4SDQ -2 8.5 kcal/mol for (AlN)(2), 1.9 kcal/mol for (AlN)(3) and -0.97 kcal/mo l for (AlN)(4). On analysing a pi-molecular orbitals diagram, only one , three and three strongly bonding pi-molecular orbitals exist for the planar four-, six- and eight-membered AlN rings, respectively.