Metal sulphide-tetraphosphorusdekasulphide phase diagrams

Abstract

The phase diagrams of the quasibinary systems Ag 2SP 4S 10, Cu 2SP 4S 10, Tl 2SP 4S 10 and Sb 2S 3P 4S 10 were determined by means of difference thermal and X-ray analyses. Ag 2SP 4S 10 contains the congruently melting compound Ag 7PS 6, the peritectic compounds Ag 3PS 4, Ag 4P 2S 7 and Ag 2P 2S 6 and the peritectoid high temperature compound Ag 7P 3S 11. The lattice parameters of Ag 3PS 4 and of a new high temperature modification of Ag 4P 2S 7 were determined: Ag 3PS 4, space group Pmn2 1, a=765.0(1), b=686.8(1), c=650.9(1) pm; HT-Ag 4P 2S 7, a=807.3(2), b=1102.2(3), c=636.8(2) pm, β=105.22(3)°. In the system Cu 2SP 4S 10 the congruently melting compound Cu 7PS 6, the peritectic compound Cu 3PS 4 and the new metathiophosphate (CuPS 3) n were observed. The IR and Raman spectra of the compounds are given. The systems Tl 2SP 4S 10 and Sb 2S 3P 4S 10 are simple. Similar to the system Ag 2SP 4S 10, miscibility gaps were found on the P 4S 10-rich side of these systems. The compounds Tl 3PS 4, Tl 2P 2S 6 and SbPS 4 (lattice parameters a=1306.03(5), c=627.9(5) pm) melt congruently.