Synthesis and Characterization of the Rubidium Thiophosphate Rb-6(PS5)(P2S10) and the Rubidium Silver Thiophosphates Rb2AgPS4, RbAg5(PS4)(2) and Rb3Ag9(PS4)(4)

摘要

The metal thiophosphates Rb2AgPS4 (2), RbAg5(PS4)(2) (3), and Rb3Ag9(PS4)(4) (4) were synthesized by stoichiometric reactions, whereas Rb-6(PS5)(P2S10) (1) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P2(1)/c (no. 14), a = 17.0123(7) angstrom, b = 6.9102(2) angstrom, c = 23.179(1) angstrom, = 94.399(4)degrees; 2 triclinic, P(no. 2), a = 6.600(1) angstrom, b = 6.856(1) angstrom, c = 10.943(3) angstrom, = 95.150(2)degrees, = 107.338(2)degrees, = 111.383(2)degrees; 3 orthorhombic, Pbca (no. 61), a = 12.607(1) angstrom, b = 12.612(1) angstrom, c = 17.759(2) angstrom; 4 orthorhombic, Pbcm (no. 57), a = 6.3481(2) angstrom, b = 12.5782(4) angstrom, c = 35.975(1) angstrom. The crystal structures contain discrete units, chains, and 3D polyanionic frameworks composed of PS4 tetrahedral units arranged and connected in different manner. Compounds 1-3 melt congruently, whereas incongruent melting behavior was observed for compound 4. 1-4 are semiconductors with bandgaps between 2.3 and 2.6 eV and thermally stable up to 450 degrees C in an inert atmosphere.