Abstract. Ab initio molecular electronic structure methods have been used to study the relative stability of the planar inorganic ring (HAlNH)n (n=24) during homodesmotic and monomer polymerization reactions. Optimized geometries, frequencies and energies through restricted Hartree-Fock/6-31G* are reported, and energies at the self-consistent field optimized geometries including Mller-Plesset fourth perturbation theory with single, double and quadruple excitation (MP4SDQ) corrections are also reported for both reactions. Homodesmotic reactions with MP4SDQ 28.5kcal/mol for (AlN)2, 1.9kcal/mol for (AlN)3 and 0.97kcal/mol for (AlN)4. On analysing a -molecular orbitals diagram, only one, three and three strongly bonding -molecular orbitals exist for the planar four-, six- and eight-membered AlN rings, respectively.