Reactions of nitrogen dioxide with chloride and bromide salts

Infrared absorption spectroscopy was used to study the reaction of nitrogen dioxide with a number of halide salts: MX (s) + 2N02 (g), XNO (g) + MN03 (s), where M = metal and X = halogen (CI, Br). This reaction was observed for the chloride and bromide salts of sodium, potassium, calcium and magnesium. These reactions do not reach thermodynamic equilibrium, and evidence is presented that they are surface controlled. These reactions are very fast and evidence is reported for the relative rates of the chloride and bromide salts. The following mechanism may explain the observed experimental results: (M+X-)(s) + N02(g) (M+X-N02)(s) (M+x-N02)(s) (M+XN02-)(s) (M+XN02-N02)(s) + N02(g) (M+XN02-N02)(s) (M+XN02-N02)(s) (M+XNON03-)(s) (M+XNON03-)(s) (M+N03-)(s) + XNO(g), where (M X-) (s), XNO (g) , and the subscript (s) refer to the halide salt, nitrosyl halide, and the solid state respectively