We calculate here using the mean field theory, the phase-line equations for
the gamma-beta, delta-beta and delta-gamma phase transitions in the NH4Brx
Cl1-x system. We fit our P-T phase diagrams calculated at various concentra
tions to the experimental data for this crystalline system. Our results sho
w that there is a good agreement between our calculated and experimentally
observed phase diagrams for the NH4BrxCl1-x system. (C) 2001 Elsevier Scien
ce B.V. All rights reserved.