Distributions of translational energy released in the loss of fluorine atoms from SF+6, CF+4 and C2F+6 ions have been investigated as a function of initial ion internal energy using photoelectron-photoion coincidence spectrometry. The distributions are dominated by high kinetic energies, representing a substantial proportion of the excess energy available to the reaction. In the case of SF+5 and CF+3 formation the distributions remain constant, despite changing available energy, within one electronic state of the parent ion. Such distributions are not consistent with the predictions of the statistical theories of unimolecular reactions, but rather indicate dissociation within a time short compared with the statistical pratition of energy among the internal modes of the reactant ion. The implications of the distributions on the nature of the ionic potential surfaces are discussed.