Chalcogenidoantimonates by Solvothermal Synthesis in Liquid Ammonia

Authors


  • Dedicated to Professor Wolfgang Bensch on the Occasion of His 60th Birthday

Abstract

A series of chalcogenidoantimonates, namely [Zn(NH3)6](SbIII4S7) (1), [Zn(NH3)6]{Zn(NH3)3SbVS4}2·NH3 (2), [Mn(NH3)6](SbIIISe2)2 (3) and [Zn(NH3)4]{Zn(NH3)SbIIISe3}2·3NH3 (4) are synthesized by solvothermal technique in liquid ammonia at 50 °C from elemental zinc or manganese, antimony and sulfur or selenium. 1 (space group Pequation image) and 2 (Pequation image) crystallize centrosymmetrically, whereas 3 (Pna21) and 4 (P21) represent polar structures. All compounds contain discrete cationic [Zn(NH3)4]2+, [Zn(NH3)6]2+, and [Mn(NH3)6]2+ ammine complexes. In the anionic structure parts, corner-connected trigonal-pyramidal SbS3 and SbSe3 are the characteristic building units. 1 and 4 contain 2D polymeric anions, in the latter case with Zn2+ cations incorporated in a selenidoantimonate(III) network. The polymeric anion in the structure of 3 is a helical chain. 2 is a molecular compound and contains dinuclear anions [S3Sb–S–Zn(NH3)3]2– with SbV. Raman measurements show the Sb–Ch valence vibrations in the expected region between 250–370 cm–1 for 1 and at 212 cm–1 for 4. According to the reflectance spectrum 4 is a semiconductor with an optical band gap of 2.05(5) eV.

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