New studies of the infrared spectra of the products which result on codeposition at approximately 5 K of a Ne: NO sample with Ne atoms that have been excited in a microwave discharge have led to new and revised assignments for several ionic species. The appearance of the nu(1) absorption of ONNO+ for several new species with asymmetric isotopic substitution, but for no symmetrically substituted species, confirms the trans ground-state configuration for ONNO+. The behavior of a neon-matrix product absorption at 1227.5 cm(-1) parallels that of an argon-matrix absorption at 1221.0 cm(-1) which has recently been assigned to trans-ONNO-. The identity of the carrier of a product absorption at 1424.1 cm(-1), contributed by a vibration of two symmetrically equivalent NO groups, has not been definitively established. This absorption exhibits complex photodestruction behavior. Three absorptions are assigned to cis, cis-(NO)(3)(-), which has C-2v symmetry, with the aid of density functional calculations of the isotopic substitution pattern for the vibrational fundamentals of this species. Similar calculations of the isotopic substitution patterns for other structures result in poor agreement with the experiments. Photodestruction of cis, cis-(NO)(3)(-) trapped in solid neon yields the N2O ... NO2- complex.