Ag₉I₃(SeO₄)₂(IO₃)₂ – Synthesis, Crystal Structure, and Ionic Conductivity

Abstract

Abstract Ag 9 I 3 (SeO 4 ) 2 (IO 3 ) 2 was obtained for the first time by reacting a stoichiometric mixture of Ag 2 O, AgI and SeO 2 at elevated oxygen pressure (255 MPa) and at a temperature of 500 °C. Ag 9 I 3 (SeO 4 ) 2 (IO 3 ) 2 was characterized by X‐ray powder diffraction, differential scanning calorimetry, impedance spectroscopy and single crystal structure analysis. The crystal structure was solved by direct methods ( I 23, Z = 8, a = 12.9584(6) Å, V = 2175.9(2) Å 3 and R 1 = 2.70 %). The crystal structure consists of isolated SeO 4 tetrahedra and trigonal IO 3 pyramids separated by Ag + and I – ions. Each four of the SeO 4 2– and IO 3 – anions aggregate, forming a novel supramolecular building block, showing a hetero‐cubane like structure. According to the results of impedance measurements, Ag 9 I 3 (SeO 4 ) 2 (IO 3 ) 2 is a good silver ion conductor. The compound shows an abrupt increase in the ionic conductivity in the temperature range of 115 to 147 °C, and has a silver ion conductivity of 7.1 × 10 –5 Ω –1 cm –1 at 25 °C. The activation energy for silver ion conduction is 0.45 eV, in the temperature range from 25 to 115°.