Terms sourced from: http://iupac.org/publications/pac/66/3/0533/

"Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994)", Ewing, M.B.;Lilley, T.H.;Olofsson, G.M.;Ratzsch, M.T.;Somsen, G., Pure And Applied Chemistry 1994, 66(3), 533