Preferred Label : miscibility;
IUPAC definition : Capability of a mixture to form a single phase over certain ranges of temperature,
pressure, and composition.;
Scope note : if a mixture is thermodynamically metastable, it will demix if suitably nucleated.
if a mixture is thermodynamically unstable, it will demix by spinodal decomposition
or by nucleation and growth if suitably nucleated, provided there is minimal kinetic
hindrance.; for a two-component mixture, a necessary and sufficient condition for stable or metastable
equilibrium of a homogeneous single phase is ¿2 dmixg
t p 0 , where dmixgis the gibbs energy of mixing and¿ the composition,
where ¿is usually taken as the volume fraction of one of the components. the system
is unstable if the above second derivative is negative. the borderline (spinodal)
between metastable and unstable states is defined by the above second derivative equalling
zero. if the compositions of two conjugate (coexisting) phases become identical upon
a change of temperature or pressure, the third derivative also equals zero (defining
a critical state).; the single phase in a mixture may be confirmed by light scattering, x-ray scattering,
and neutron scattering.; whether or not a single phase exists depends on the chemical structure, molar-mass
distribution, and molecular architecture of the components present.;
Origin ID : MT07230;
See also
Capability of a mixture to form a single phase over certain ranges of temperature,
pressure, and composition.
