  The thermodynamic activities of all components in Ga-In-Tl system have been
predicted at 1073, 1173 and 1273 K, using Molecular interaction volume model
(MIVM). The infinite dilute activity coefficients for Ga-In and Ga-Tl binary
subsystems, which were needed for the determination of thermodynamic activities
of all components in Ga-In-Tl, have been predicted by using a method that is
based on Complex formation model for liquid alloys. The computed thermodynamic
activities of Ga in Ga-In-Tl were observed to satisfactorily agree with the
available experimental data when the newly computed coefficients were applied
in MIVM. The satisfactory prediction of the activity of Ga led to the
prediction of the activities of the remaining two components (In and Tl).
Iso-activities of all components (Ga, In and Tl) were plotted, and they reveal
the dependence of the nature of chemical short range order in Ga-In-Tl system
on composition.
