Homogeneity regions, preparation and analysis of single crystals of certain compounds of Cs(Tl)X-Ge(Sn, Pb, Cd)XΛ2 systems, where X-Cl, Ber, I

Using the quantitative differential-thermal analysis alloys in the range of the compounds TlGeIΛ3, TlSnIΛ3, TlSnΛ2JΛ5, TlPbIΛ3, TlΛ3PbIΛ5, TlΛ3PbBrΛ5, TlPbΛ2BrΛ5, CsCdClΛ3, CsCdBrΛ3, CsΛ2CdBrΛ4, TlCdClΛ3, TlCdBrΛ3, the corresponding microdiagrams of state are plotted. It is established, that the maximum points on state microdiagrams of CsCdClΛ3, TlΛ3PbIΛ5 and TlΛ3PbBrΛ5 are shifted as to stoichiometric compositions to the side of more fusible component by 0.80, 0.20, and 0.40 mol.% respectively. At the temperatures of eutectic horizontals the compounds TlCdClΛ3, CsCdClΛ3, TlΛ3PbIΛ5, TlPbΛ2BrΛ5, TlCdClΛ3 and TlGeIΛ3 have the widest homogeneity regions, and CsCdBrΛ3 and CsΛ2CdBrΛ4 - the narrowest ones. It is shown, that characteristic changes of the values of homogeneity regions and melting enthalpies of the compounds TlGe(Sn, Pb)IΛ3 in the direction Ge→Sn→Pb are related to the phenomenon of secondary periodicity, and the decrease in the homogeneity region for TlΛ3PbXΛ5 type compounds in the direction I→Br - to the decrease in halide-ion radii