Critical constants of pure fluids (as important reference data in construct
ing vapour-liquid phase diagrams and basic input of various estimation meth
ods) were determined for systems of non-spherical Kihara molecules; values
of the critical temperature, density, compression factor and pressure of fl
uids composed of prolate and oblate molecules were evaluated from the fourt
h-order virial expansion. The second and third virial coefficients of the K
ihara molecules were determined by applying the recently proposed method in
which the effect of molecular core geometry and functional dependence of a
pair interaction on the surface-surface distance are factorized and the fo
rmer contribution determined from a formula for the corresponding hard conv
ex body virial coefficient. The virial expansion for non-spherical Kihara m
olecules is applied to determine the critical constants of n-alkanes (metha
ne to octane) and cyclic hydrocarbons (cyclopentane, cyclohexane, benzene a
nd naphthalene); a fair agreement with experimental data was found.