The results of investigations of the distribution of fluorocarbons in two-phase solid phase–gas and liquid–vapor systems based on uranium hexafluoride are presented. The systems are studied under equilibrium conditions, under which a constant distribution of fluorocarbons is established between the phases in a closed volume, and under nonequilibrium conditions created with stationary removal of the gas phase from the volume with liquid or solid uranium hexafluoride. The investigations were performed on specially prepared standard mixtures of uranium hexafluoride with fluorocarbon fraction from 10–4 to 10–1%. The special features of the evaporation processes in the two-phase systems studied are shown, the distribution laws of the fluorocarbons between phases of the main substance are established, and the regimes of evaporation of the mixtures with the smallest disruptions in the uniformity of the fluorocarbon inflow with the flow of the evaporated uranium hexafluoride are determined.