Synthesis and Physicochemical Properties of a Lanthanum-Containing Analog of the Mineral Berthierite FeSb2S4

Abstract

Phase equilibria in the FeSb2S4–FeLa2S4 system were studied by physicochemical analysis methods (differential thermal, X-ray powder diffraction, and microstructural analyses and microhardness and density measurements), and the phase diagram of the system was constructed. The formation of quaternary sulfide FeLaSbS4 melting congruently at 1230 K, an analog of the mineral berthierite FeSb2S4, was detected. The X-ray powder diffraction analysis showed that FeLaSbS4 belongs to the berthierite structural type and crystallizes in the orthorhombic system with the unit cell parameters a = 11.424 A, b = 14.160 A, c = 3.782 A, Z = 4, and space group Pbam.