Structural aspects and ac conductivity of the solid electrolyte Ag<inf>x</inf>Cu<inf>2-x</inf>HgI<inf>4</inf>

Lattice parameters of the solid electrolyte AgxCu2-xHgI4 have been determined for the different values ofx between 0 and 2. All compositions studied showed a tetragonal phase, except for a small range fromx = 1.14 tox = 1.30. Compositions in this range had a cubic phase. The lattice parametersa andc of compositions outside this range increased steadily from 6.07 and 12.15A °, respectively, forx = 0 (Cu2HgI4) to 6.29 and 12.55A °forx = 2 (Ag2HgI4). Compositions in the region1.14 ≤ x ≦ 1.3 that had cubic phases were found to have lattice parametera between 6.22 and 6.26A °. The frequency-dependent conductivity of all compositions showed two distinct regions at low temperatures: a frequency-independent plateau region at lower frequencies (1 Hz to 10 kHz) and a power law variation,Aωn, at higher frequencies (10 to 65 kHz). At higher temperatures (>328 K) electrode polarization effects were seen at low frequencies and a frequency-independent plateau region at higher frequencies. The frequency-independent (i.e., dc) conductivity was on the order of 10-5 (Ω cm-1) for compositions1.14 ≤ x ≤ 1.3. © 1992 Academic Press, Inc. All rights reserved.