Berthelot equation of state

$RT=(p+\frac{a}{T{v}^2})(v-b)$

where

$a=\frac{27}{64}{R}^2\frac{T_c^3}{P_c}$

and

$b=\frac{R{T}_c}{8P_c}$

where $p$ is the pressure, $T$ is the temperature and $R$ is the molar gas constant. $T_c$ is the critical temperature and $P_c$ is the pressure at the critical point.

References

1. D. J. Berthelot "", J. Phys., 8 pp. 263- (1899)