Infrared Spectrum, Structure, and Bonding of Lithium Nitroxide, LiON

Lithium nitroxide has been formed through reaction of lithium atoms and nitric oxide in solid argon at high dilution. Isotopic substitutions at all atomic positions verify the molecular identity and furnish an ample basis for normal-coordinate analysis. The data indicate the molecule is bent (100°±10°), and they favor the molecular formula LiON (rather than LiNO). Potential constants kNO=7.97 mdyn/Å, kLiO=1.33 mdyn/Å, kα=0.54 mdyn·Å/rad2, and kLiO,α=0.39 mdyn are obtained. The force constants can be correlated to those of other molecules with the aid of the electronegativity of lithium. The bonding is not readily explained; the NO bond has a bond order near 1.7, significantly weaker than that in HNO.