Physico-chemical interaction in the Tl2Se–HgSe–DIVSe2 systems (DIV – Si, Sn)

Phase equilibria in the quasi-ternary systems Tl2Se–HgSe–DIVSe2 were investigated by XRD method. Isothermal sections of the systems at 520 K were constructed. Quaternary compounds Tl2HgDIVSe4 were found at this temperature in both systems. They crystallize in the non-centrosymmetric tetragonal space group I 4 ¯ 2 m with the lattice parameters a = 0.80032(3) nm, c = 0.66879(4) nm (RI = 0.0762, RP = 0.1199) for Tl2HgSiSe4, and a = 0.80407(1) nm, c = 0.68852(2) nm (RI = 0.0746, RP = 0.1158) for Tl2HgSnSe4.