This paper uses results from statistical mechanical theory, applied through a combination of an extended principle of corresponding states with some knowledge of intermolecular potentials, to the calculation of the transport and equilibrium properties of gas mixtures at low density. The gases involved are: N2, O2, NO, CO, CO2, N2O, CH4, CF4, SF6, C2H4, C2H6, and He, Ar, Ne, Kr, Xe. The properties included are: second virial coefficient, viscosity, diffusion, and thermal diffusion, but not thermal conductivity. The calculations are internally, thermodynamically consistent and the resulting algorithms, which are fully programmable, operate in an entirely predictive mode by means of validated combination rules. This paper is a sequel to one on the five noble gases and all their possible mixtures and a second on the above eleven polyatomic gases. The paper contains ten tables (mainly intended for the checking of computer codes) and 201 graphs of deviation and comparison plots. An additional 98 tables have been deposited with the Physics Auxiliary Publication Service (PAPS) of the AIP. The algorithms presented in this paper, together with those mentioned above, make it possible to program calculations for a wide range of low density equilibrium and transport properties of 16 gases and of all possible multicomponent mixtures formed with them, for a total of 65,535 systems. For each system, the program would cover the full range of compositions. © 1990, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved.