The synthesis, structure, and acid-catalyzed degradation of N-nitrosohydroxylamine-N-sulfonate has been subjected to analysis by ab initio molecular-orbital calculations using a cc-pVTZ basis set, further refined using density functional theory at the Becke 3LYP level using the 6-311+G(3d) basis set. The theoretical data is compared to the structural data obtained from the redetermination of the X-ray crystal structure of this seminal anion. This comparison allows a unique insight into the mechanism behind nitric oxide coupling and its reductive elimination as nitrous oxide. These processes are of direct relevance to the action of metalloenzymes such as nitrite reductase and the underlying mechanism of Wacker type catalysts for the dismutation of nitric oxide into nitrogen and oxygen (2NO --> N2O --> N-2 + 1/2O(2)).