Phase Diagram of the TbBr3-KBr Binary System

Abstract

The phase equilibrium of the TbBr3-KBr has been established by Differential Scanning Calorimetry. This system has the three compounds K3TbBr6, K2TbBr5, and KTb2Br7 and two eutectics located at (χTb = 0.163 (885 K) and (χTb = 0.433 (697 K). K3TbBr6 undergoes a solid-solid phase transition at 691 K and melts congruently at 983 K with the corresponding enthalpies 8.0 and 48.0 kJ mol−1. K2TbBr5 melts incongruently at 725 K, and KTb2Br7 at 741 K. The latter forms at 694 K, a temperature very close to that (697 K) of one of the two eutectics also existing in the binary system.