Electrical conductivity and composition range of Ag2HgI4 between room temperature and 75°C

Where the extraordinaries meet: a cascade of isosymmetrical superionic phase transitions and negative thermal expansion in a novel silver salt-inclusion borate halide

“…43 However, they exceeded the conductivity values for β-AgI (10 −8 S cm −1 at 60 °C) and Ag 2 HgI 4 (10 −4 S cm −1 at 60 °C). 44 Most likely, the kinetics of phase transitions in Ag 3 B 6 O 10 I depend on the heating rate, and it is possible that the hightemperature α phase can be quenched at room temperature.…”

“…43 However, they exceeded the conductivity values for β-AgI (10 −8 S cm −1 at 60 °C) and Ag 2 HgI 4 (10 −4 S cm −1 at 60 °C). 44…”

Optical Spectroscopy of the Superionic Crystals

“…While discussing the imperfection of AgI-type superionics one has to take into account two peculiarities, namely the large number of stoichiometric defects and the tendency of multiphase system formation for ternary compounds. For example, Ag,(, -,HgI,, +a) crystals are homogeneous in a rather narrow range of deviations from stoichiometry (0.24 > 6 > -0.33); outside this range X-ray analysis detects either AgI or HgI, inclusions [162]. MAg,I, compounds are thermodynamically unstable below and at room temperature decomposing into AgI and M,AgI,.…”

“…For the regions where Ag,HgI, crystals coexist with either AgI or HgI,, as is evidenced by optical spectra, an additional, broad low-temperature maximum appears on Ac,(T) plots (as in the case of calorimetric curves for Ag2HgI, powders prepared with stoichiometry violation). The analysis of calorimetric and optical data on solid phase crystals and powder samples of different stoichiometric compositions with the account of the Ag,HgI, phase diagram [162] enables one to assume [170] the appearance of the additional lowtemperature peculiarity on the heat capacity plots, i.e. the PT temperature decrease for some samples, to be due to deviation from stoichiometry as well as to the phase boundary effects.…”

Dielectric properties of nanophase Ag2HgI4 and Ag2HgI4-Al2O3 nanocomposites

“…But α-Ag 2 HgI 4 is a highly conducting phase in which the three cations have four equivalent lattice sites where the cations are continuously distributed. In both the phases the charge transport is predominantly by silver ions (Leute and Rusche 1981). Many authors (Neubert and Nichols 1958;Browall and Kasper 1975;Kezionis et al 1984) have studied the electrical properties of this material.…”