Equations implemented in PHREEQC (under construction)

Thermodynamic constants (K's) dependency to temperature and pressure (Appelo et al., 2014 and Wikipedia)

$$ \ce{ \alpha~A + \beta~B <=> \gamma~C + \delta~D } \qquad \qquad K_{T,P} $$
$$ \Delta\overline{V}_r = (\gamma~\overline{V}_C + \delta~\overline{V}_D) - (\alpha~\overline{V}_A + \beta~\overline{V}_B) $$
$$ log~K_{T,P} = log~K_{T,P=1} - \frac{\Delta\overline{V}_r \cdot (P-1)}{2.303 \cdot R \cdot T} $$
\(K_{T,P}\) is the \(K\) value at \(T\) and \(P\) ; \(K_{T,P=1}\) the \(K\) value at \(T\) and \(P=1~atm\) (when 0 < \(T\) < 100 °C) or at \(P=P_{SAT}\) (saturation vapor pressure of water, when 100 < \(T\) < 374 °C) ; \(\Delta\overline{V}_r\) is the reaction's volume change at \(T\), \(P\) and aqueous solution ionic strength ; and \(R\) is the ideal gas constant. \(Log~K_{T,P=1}\) is calculated by either the van't Hoff equation (-log_k and -delta_h) or the polynomial (-analytic). \(\overline{V}_i\)'s are retrieved by the VM("Aqueous species") and PHASE_VM("Phase") PHREEQC BASIC functions.