Reactions of laser-ablated Sc. Ti. V. Cr, and Mn with NO in excess neon give the same major products found in excess argon with several interesting differences. The argon-to-neon matrix shifts range from +43 cm(-1) for the small Sc[NO](+) cation to -5 cm(-1) for Sc[NO]. The lower polarizability of neon leads to a slower condensation rate and allows more reagent diffusion and reaction under the conditions of these experiments, and as a result, higher nitrosyls a-re observed on condensation in excess neon. Another consequence of the slower condensation rate of neon is the inability to trap as much of die side-bound M[NO] Precursor relative to the NMO insertion product: higher yields of M[NO] species are trapped in solid argon. An advantage of the greater inertness of neon is its ability to trap cations with less perturbation than argon. Model calculations show that argon interacts more strongly with Sc[NO](+) than with neon: the ArSc[NO](+) species is stable and has a lower N-O stretching frequency than NeSc[NO](+). New CCl4 doping experiments and DFT calculations confirm the new observation of V[NO](+) and the previous identification of Cr(NO)(3)(-), which is a stable anion that might be observable in the gas phase.