Abstract
The models of melamine-trimer were composed of the most stable C2v model of melamine-dimer (MA (180)) previously determined by the CNDO/2 method. The three models obtained are most stable among the six models and their energies are almost same each other. The valence electron charge density, π-charge density, and π-bond order of the trimer models are not so different from those of melamine, methylolmelamine, and melamine-dimer models. Therefore, the calculated results suggest that the electronic properties of methylolmelamines, melamine-dimer, and melamine-trimer mainly result from that of melamine ring. The effect of methylation on the electronic property of melamine-oligomer seems to be small.
