ChemInform Abstract: Local and Permeating Disorder of Copper(I) Cations in Cu3BiS2Br2 and Cu4Bi3S5Br3-xClx (x = 1.19)

✍ Scribed by Andreas Heerwig; Fabian Nitsche; Michael Ruck

• Publisher: John Wiley and Sons
• Year: 2011
• Weight: 22 KB
• Volume: 42
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.201111003

✦ Synopsis

Local and Permeating Disorder of Copper(I) Cations in Cu 3 BiS 2 Br 2 and Cu4Bi3S5Br3-xClx (x = 1.19) -Cu3BiS2Br2 (I) and Cu4Bi3S5Br1.81Cl1.19 (II) are synthesized from stoichiometric mixtures of Cu, Bi2S3, S, CuCl, NaCl, and CuBr (silica ampules, 570 °C, 14 d) and characterized by powder and single crystal XRD. (I) crystallizes in the orthorhombic space group Pnma with Z = 4 and (II) in the monoclinic space group I2/m with Z = 4. Both compounds exhibit networks of thio-halogenido-bismuthate(III) polyhedra sharing corners, edges, and faces. The Cu + cations are spread over numerous contiguous trigonal or tetrahedral voids. Compound (II) contains a continuous pathway for copper ion transport and one-dimensional copper ion conductivity is expected. The smooth formation of mixed halogenides opens the opportunity for band-gap tuning, which is essential for the optimization of thermoelectric properties within this wide family of compounds.