A selected ion flow tube apparatus was used to investigate the positive ion chemistry of two derivatives of SF6β; SF5βCF3β and SF5βCl. This represents the first investigation of the positive ion chemistry of SF5βCl, and much of the data on SF5βCF3β is being presented here for the first time. Rate coefficients and ion product branching ratios have been determined at room temperature (300 K) for reactions with the following twenty-two cations; Ne+, F+, Ar+, N2+β, N+, CO+, CO2+β, O+, N2βO+, H2βO+, O2+β, SF4+, CF2+β, SF+, SF2+β, NO2+β, SF5+β, NO+, CF+, CF3+β, SF3+β, and H3βO+ (listed in order of decreasing recombination energy). Comparisons are made in the text for the reactions of these ions with SF6β. SF2+β, NO2+β, NO+, SF3+β, and H3βO+ are found to be unreactive with both of the derivatives. The majority of the other reactions proceed with rate coefficients which are close to the capture value. The exceptions are the reactions of O2+β, SF+, SF5+β, and CF3+β with SF5βCF3β, and SF4+ and SF5+β with SF5βCl, all of which have rate coefficients significantly less than the capture mechanism value. Several distinct processes are observed among the large number of reactions studied, including dissociative charge transfer and various abstraction channels. Non-dissociative charge transfer is not observed, implying that any parent ions formed dissociate rapidly to the fragment ions and associated neutrals