Synthesis and study of the properties of synthetic analogues of the mineral naffildite with the participation of rare earth elements

In recent years, there has been a significant increase in interest ternary and quaternary compounds with the participation of rare earth elements (REE), as well copper, antimony, bismuth, which have wider range physical properties. Due to their valuable properties, they become promising targets research for modern materials science. Therefore, purpose this work is study properties synthetic analogues naffildite elements. The samples were synthesised from sulphides (in case obtaining Cu2LaSb3S7, Cu2CeSb3S7, Cu2PrSb3S7 Cu2NdSb3S7) by fusion sealed quartz ampoules, preliminarily evacuated residual pressure 10-3 mmHg at 950–1100 K 8 hours. remaining antimony bismuth-containing analogues, due peritectic nature formation, through batches (2Cu + Ln 3Sb(Bi) 7S) especially pure After completion reaction, homogenizing annealing was carried out month 600–700 K, depending on composition. obtained investigated differential thermal (DTA), X-ray phase (XRD) microstructural (MSA) analyzes, bymeasuring microhardness determining density. Compounds Cu2LnSb3S7 or Cu2LnBi3S7 (Ln – REE) type direct synthesis ligature CuSbS2(CuBiS2) LnSbS3(LnBiS3). It found that are sostructural crystallize orthorhombic system (Cu2LnSb3S7 = 14.490÷14.264, b 21.422÷21.206, c 3.902–3.804 Å; 14.722÷14.506, 21.864÷21.564, 4.142÷3.464 Z 4, simple group Pbnm Pbn21) belong structure Pb2Cu (Pb, Bi) Bi2S7. Cu2NdSb3S7 melt congruently 975, 985, 1015 respectively, other formed reaction.