Valence bond and molecular orbital studies of three N2O isomers, and valence bond representations for some azide decompositions

The results of STO-6G valence bond calculations with Lewis-type valence bond structures are reported for the S=0 spin ground states of the linear NNO (C∞v) and NON (D∞h) isomers of N2O. It is calculated that the singlet diradical character of the NON isomer is substantially larger than for the NNO isomer. The results of B3LYP/6-31G(d) density functional calculations are also reported for the C∞v and D∞h ground states, the single-determinant approximations to the lowest-energy S=1 spin excited states of these two isomers, and for the triangular C2v isomer. The calculated bond lengths are in accord with qualitative valence bond considerations.