[2] Analytical evaluation of third and fourth virial coefficients for hard disk fluids in narrow channels and equation of state. Physica A Statistical Mechanics and its Applications (2020).

Equation 3 assumes that Equation 4 is correct. Two examples explain the use of this equation. Methane (B 1 ) and ethane (B 2 ) have B factors at 0° C. of -53.28 and -219.38, respectively.

Kammerlingh-Onnes proposed the virial equation of state shown in Equation 7. 19 20 And B, C, …are not constants but functions of temperature called the second, third,…virial coefficients.