Abstract
From a comparative study of the mass spectra of furane, 2, 5‐dimethylfurane, tetrahydrofurane and 2‐methyltetrahydrofurane, it is shown that despite apparent differences in the characteristics of the ionic abundances very similar decomposition patterns are in all cases responsible for the observed mass spectra.Some typical rearrangements, mostly including the heteroatom, are also considered.