https://doi.org/10.1351/goldbook.F02543
Of a substance B, \(f_{\rm{B}}\) or \(\tilde{p}_{\rm{B}}\), in a gaseous mixture is defined by \(f_{\rm{B}}=\lambda _{\rm{B}}\ \lim _{p\rightarrow 0}\frac{p_{\rm{B}}}{\lambda _{\rm{B}}}\), where \(p_{\rm{B}}\) is the partial pressure of B and \(λ_{\rm{B}}\) its absolute activity.
See also:
PAC, 1984, 56, 567. (Physicochemical quantities and units in clinical chemistry with special emphasis on activities and activity coefficients (Recommendations 1983)) on page 571 [Terms] [Paper]
PAC, 1994, 66, 533. (Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994)) on page 539 [Terms] [Paper]
PAC, 1984, 56, 567. (Physicochemical quantities and units in clinical chemistry with special emphasis on activities and activity coefficients (Recommendations 1983)) on page 571 [Terms] [Paper]
PAC, 1994, 66, 533. (Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994)) on page 539 [Terms] [Paper]