AbstractThe most prominent ion in the mass spectra of C6F5CH2X (X  H, Br, CH:CH2, COCl, and CH2C6F5) is C7F5H2+, formulated as the pentafluorotropylium cation. This ion is also found, in an amount comparable to the parent ion, in the spectrum of (C6F5)2CH2. The heptafluorotropylium cation is found similarly in the spectrum of C6F5CF3. The mass spectra of (C6F5)2CHBr and [(C6H5)2CH]2exhibit an ion C13F10H+as the base peak, which is probably a pentafluorophenylpentafluorotropylium cation.The alcohol (C6F5)2CHOH shows loss of C6F5, followed by 2H, as a major breakdown pathway.The mode of formation, and the subsequent fragmentation, of the major ions in these spectra, are discusse