  The Modified Quasichemcial Model in the Distinguishable-Pair Approximation
(MQMDPA) for manifold short-range orders in liquids has been successfully
extended to multicomponent solutions. The extension is conducted by means of
the geometrical interpolation method. Three types of interpolation models,
namely Kohler, Toop and Chou, are introduced to initially formulate the pair
interaction energies in ternary solutions by employing those in their
constituent binary solutions. The pair energies can be expanded in terms of the
pair fractions (configuration-dependent) or in terms of the
coordination-equivalent fractions (composition-dependent). These methods are
subsequently extended for use in multicomponent solutions. A general formalism
for the combined Kohler-Toop model is employed to permit complete freedom of
choice to treat any ternary subsystems with a symmetric or asymmetric model.
Meanwhile, a general Chou model is also used to treat all ternary subsystems
without any human interference to select symmetric or asymmetric components but
only dependent upon the similarity and difference in properties from each two
binary solutions with a co-member. Advantages and shortcomings are critically
discussed regarding the utilization of different interpolation models.
