Synthesis, Crystal Structure, and Thermodynamic Functions of GeSnSb4Te8

Abstract

A quaternary compound GeSnSb₄Te₈ formed in the GeSnSb₂Te₄–SnSb₂Te₄ system in a ratio of GeSnSb₂Te₄ : SnSb₂Te₄ = 1 : 1 is studied for the first time with various physicochemical methods and thermodynamic calculations in a wide temperature range. The compound GeSnSb₄Te₈ melts congruently at 950 K. The enthalpy of the formation Δ\(H_{{298}}^{0},\) standard entropy \(S_{{298}}^{0},\) and isobaric heat capacity \(c_{{p,298}}^{0}\) of this compound are –254.3 kJ mol^–1, 787.2 J mol^–1 K^–1, and 342.6 J mol^–1 K^–1, respectively. Single crystals of GeSnSb₄Te₈ are obtained via chemical transport reactions. The unit cell parameters of the GeSnSb₄Te₈ compound crystallized in a rhombic syngony are as follows: a = 4.92 Å, b = 9.70 Å, c = 11.28 Å, space group is P_nnm, V = 837.44 ų, and Z = 2.