Mesoionic compounds—XIX: Mass spectral fragmentation patterns for some five-membered systems containing oxygen,nitrogen and sulfur

Mesoionic compounds of the s-triazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole, 1,2,3-thiadiazole, 1,3-thiazole and 1,3-dithiole systems all underwent deep-seated decomposition on electron-impact to small stable ions, determined to a large extent by the nature of the peripheral heteroatoms and the exocyclic substituent. In some instances fragmentation most probably involved an open-chain isomer of the cyclic system.