The virial coefficient is a basic thermophysical property that represents the nonideal behavior of real gases. A modified form of the well-known Weber correlation for third virial coefficients was developed based on the corresponding-states principle. The new correlation is linked to the second virial coefficients so that the prediction uncertainties can be offset to a large extent by the fact that the second and third virial coefficients are correlated. The input parameters were reduced to be consistent w...