Mass spectra of dihalogenocycloalkanes

The mass spectra of the dichloro- and bromochloro-cyclobutanes, the dichlorocyclopentanes, and the dichloro-, chlorofluoro-, and stable dibromo-cyclohexanes are reported. Four major breakdown pathways can be distinguished, the favoured fragmentation route depending on the ring size, the type of halogen substitution, the the relative position, and cis-trans-relationships of the two substituents. Within one set of isomers, the 1,1 -isomer and the cis-1,2-isomer had clearly distinguishable spectra, but the spectra of the other isomers were similar.