Electron impact studies. XCVIII. Negative ion mass spectra of the carbonyl group. The aryl-CO- and aryl-COCO- systems.

Collision-induced decompositions of molecular anions of the general formula aryl-CO-alkyl yield aryl- ions. The aryl-CO-aryl group is stable under these conditions. Parent anions from α-dicarbonyl systems do not generally fragment but, in the case of o-nitrobenzil, fragment anions are produced after cyclization of the nitro group at both carbonyl centres.