Phase relations along the Ag8GeS6[(AgBr)4GeS2] cross-section.
Crystal structure and electric conductivity of Ag6GeS4Br2 in bulk

 

Chem. Met. Alloys 3 (2010) 161-168

 

Mykola V. MOROZ, Pavlo Yu. DEMCHENKO, Lev G. AKSELRUD, Oleksiy G. MYKOLAYCHUK, Roman E. GLADYSHEVSKII

 

The -diagram of the Ag8GeS6[(AgBr)4GeS2] polythermal cross-section has been constructed in the range 25-100 mol.%Ag8GeS6. The conditions for solid-state synthesis of the Ag6GeS4Br2 quaternary phase have been established. The crystal structure of Ag6GeS4Br2 (Pnma  d 8c7a, oP96-44.24, Z = 4, a = 6.53892(5), b = 7.72656(5), c = 22.90338(17) Å; X-ray powder diffraction, 820 reflections measured, 58 parameters refined, RI = 0.0383, Rp = 0.0408, Rwp = 0.0528, χ2 = 1.76) is a disordered variant of the structure determined previously on single crystal data. The electrical conductivity of Ag6GeS4Br2 has been measured by the dc probe method between 250 and 410 K. A model for the superionic electrical conduction mechanism is proposed.

 

 

Bulk crystal structure of Ag6GeS4Br2 (left) and temperature dependences of the electrical conductivity (right).

 

Keywords

AgGeSBr / Phase diagram / Crystal structure / Electrical conductivity / Superionics