AbstractThe mass spectra of pyridazines and theirN‐oxides is reported. Previous electron impact studies on aromatic amineN‐oxides reported the appearance of M‐16 and/or M‐17 ion peaks as the usual feature of the fragmentations. In our experiments, the representative fragmentation of the pyridazineN‐oxides involves formation of a M‐30 (M‐NO) ion. The fragmentation patterns substantiated by extensive high resolution studies and the analysis of the appropriate me