Berthelot equation of state
where Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a} is an empirical constant.
References
- D. J. Berthelot "", J. Phys., 8 pp. 263- (1899)