Quantity characterizing the
deviation of the
solvent from ideal behaviour referenced to
Raoult's law. The osmotic
coefficient on a molality basis is defined by:
and on an amount fraction basis by:
where
and
are the chemical potentials of the solvent as a pure substance and in solution, respectively,
is its molar mass,
its amount fraction,
the
gas constant and
the temperaure. The latter osmotic
coefficient is sometimes called the rational osmotic
coefficient.
Source:
PAC, 1994, 66, 533
(Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium
constants for pure and mixed phases (IUPAC Recommendations 1994))
on page 546
