Frozen samples of twelve alkanes and benzene were irradiated by Cf 252 fission fragments in order to study secondary ion emission by means of time-of-flight mass spectroscopy. The mass spectra are to a certain extent similar to electron-impact spectra of gaseous samples. The pattern of the negative ions could be assigned to dissociation after electron capture and frequent collisional reactions in the destruction zone of the nuclear track. Due to the substructure of the mass spectra we emphasize that the bonding type of the negative hydrocarbon ions is mostly acetylenic. The positive ion spectra strongly depend on the structure of the original molecules. They exhibit - contrary to the negative ion spectra - molecular ions, cluster ions and molecule-specific fragment ions. Model calculations were used to investigate the possible synthesis of carbon clusters inside an expanding plasma from the infratrack. For the ultratrack earlier molecular fragmentation calculations are supplemented by modelling the dehydration which is best fitted if assumed to take place subsequent to the fragmentation on a thermal time scale. The molecular cluster distributions are calculated by an explosive breakup model of sputtered material.