Binary diffusion coefficients are reported for the systems Ne-CO,, Kr-C02 and Xe-C02 over the temperature range 277 -323 K, and combined with accurate second virial coefficients to obtain (m, 6, 8) potentials for the unlike-interactions. These potentials, together with others for the likeinteractions, have been used to calculate binary viscosities for comparison with existing data. Ber. Bunsenges. Phys. Chem. 85, 655-657 (1981) -0 Verlag Chemie GmbH, D-6940 Weinheim, 1981.