Nitrous oxide, reaction + metal atoms

However, all exothermic reactions do not react with unit efficiency, as is clearly evident in the case of nitrous oxide reacting with atomic metal cations. In extensive experiments with nitrous oxide, rate constants and product branching ratios for the reaction of 67 atomic metal cations were measured. The reaction efficiencies are plotted as a function of metal cation OA in Figure 8.3. In reactions with nitrous oxide a significant number of metal cations react with only moderate to low efficiency, despite being strongly exothermic. As discussed by Bohme and co-workers and by Armentrout et al., this apparent lack of reactivity can be related to the electronic structure of reactants, products and possible interconnecting transition states. 

Andrews and co-workers have used the matrix reaction between lithium atoms and some inorganic compounds to produce species of spectroscopic interest. Reaction of lithium with molecular oxygen [301] produces, in addition to the molecule Li02, the molecule LiO and a dimer Li2 02. Reaction with nitric oxide produced a nitroxide compound [302], but analysis of the infrared spectrum indicated that in this compound the lithium atom was bound to the oxygen atom (LiON), rather than to the nitrogen atom (LiNO), as would be expected by analogy with the known compounds HNO and RNO. The matrix deposition of lithium and nitrous oxide [303] leads to the formation of LiO and LijO. The other alkali metals have also been reacted in the same way with nitrous oxide [304]. Potassium, rubidium and caesium all led to the formation of the compounds MO and M2O. No sodium oxides were produced when sodium and nitrous oxide were co-deposited. This is to be compared with the mechanism advanced for the sodium-catalysed gas-phase reaction between N2O and CO, where sodium is assumed to react with N2O, (Section 4, ref. 

Figure 8.3 Plot of reaction efficiency and product-branching versus metal-ion-O-atom affinity for the reaction of 53 atomic cations reacting with nitrous oxide.

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