Ag3SBr and Ag 3SI: Ionic conductivity of their modifications in the T range 93-573K

Ag 3SBr and Ag 3SI obtained through a modified preparation procedure have been investigated in the temperature range 93-573K by means of conductivity, DTA and X-ray diffraction determinations. At the phase transition temperatures the Arrhenius plot of the conductivity shows evident discontinuities, whereas in the T range where Ag 3SBr and Ag 3SI have an antiperovskitic structure this plot shows an upward curvature: for Ag 3SBr a reproducible `knee' is also observed. The general behaviour of the conductivity in the wide investigated T range suggests a direct comparison between these salts and RbAg 4I 5 which shows analogous phase transitions and discontinuities in the Arrhenius plot of the conductivity. Electronic conductivity determinations confirm that the charge transport is predominantly ionic in either compound.