  In this study methods of statistical thermodynamics were applied to white tin
- grey tin equilibrium to find if there is any correlation between Debye
temperature of an additive and its effect on the equilibrium. Gibbs free energy
of the transition was calculated for a composite system comprised of tin and
the additive in assumption of Debye temperature of the composite system being a
linear combination of Debye temperatures of the components with their
respective molar fractions as weighing coefficients. Calculations showed that
additives which Debye temperatures are above 214oK should stabilize grey tin,
while the additives with Debye temperatures below 214oK should stabilize the
white one. Devised rule corroborates with all previously reported experimental
data on the effect of different additives on the transition. Predictions of the
rule about non reported additives provide a mean for its experimental
verification.

Statistical Mechanics