Synthesis and properties of compounds of the type A(III)B/sub 2/(VI)X/sub 4/(VI), A(III)B/sub 4/(V)X/sub 7/ (VI), and A/sub 3/(III)B/sub 4/(V)X/sub 9/(VI)

The physicochemical properties of europium and ytterbium chalcostibnites and bismutites are shown. The temperature dependences of the electrical conductivity of EuSb/sub 2/S/sub 4/, EuSb/sub 2/Se/sub 4/, and EuSb/sub 2/Te/sub 4/ are shown with the thermo-emf. From the x-ray phase analysis of the materials studied, it was established that they crystallize in the rhombic system with the formation of stibnite-like structures. Crystallochemical analysis of ternary tellurides of rare-earth elements with bivalent metals (Pb, Ca, Ba, Sr) showed that they have a face-centered cubic lattice of the Th/sub 3/P/sub 4/ type. The thermal expansion of compounds of the type EuSb/sub 2/C/sub 4/ and EuB1/sub 2/C/sub 4/ (C - S, Se, Te) in the interval 77-400 K was also studied.