The configurational entropy of mixing of interstitials solid solutions

A simple and general expression for the configurational entropy of mixing of multicomponent interstitials solid solutions is deduced based on a probabilistic approach to compute the configurational entropy. The good agreement obtained with previous experimental and theoretical works based on Monte Carlo and partial configurational entropy calculations in binary systems show that the expression is suitable to be used as a reference state to compute the excess thermodynamic functions in multicomponent interstitials solid solutions. The results show that the configurational entropy can be computed to a high degree of accuracy in some systems without the use of a computer.