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Temperature-induced changes in the single-crystal structure of K{sub 9}H{sub 7}(SO{sub 4}){sub 8} {center_dot} H{sub 2}O

Journal Article · · Crystallography Reports
; ; ;  [1];  [2];  [1]
  1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
  2. European Synchrotron Radiation Facility (France)
Interest in superprotonic crystals of M{sub m}H{sub n}(XO{sub 4}){sub (m+n)/2} is associated with the solution to the fundamental problem of modern condensed matter physics: investigations of structural phase transitions and the stabilization of phases with high proton conductivity with the aim of designing new functional materials. The available data suggest that changes in the physical properties in these crystals can occur through different structural mechanisms. To reveal the structural conditionality for anomalies in the physical properties, the crystals of K{sub 9}H{sub 7}(SO{sub 4}){sub 8} {center_dot} H{sub 2}O were studied by X-ray diffraction in the temperature range of 25-463 K, and the crystal structure of the high-temperature phase was determined at 418 K (sp. gr. Pcan). The results of the study indicate that the occurrence of high conductivity in K{sub 9}H{sub 7}(SO{sub 4}){sub 8} {center_dot} H{sub 2}O crystals at high temperatures is associated with the diffusion of water of crystallization, the hydrogen-bond network rearrangement, and the motion of K ions. The hydrogen-bond rearrangement and the hindered back diffusion of water to the crystal stabilize the high-temperature phase and ensure its supercooling to low temperatures.
OSTI ID:
22113627
Journal Information:
Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 3 Vol. 58; ISSN 1063-7745; ISSN CYSTE3
Country of Publication:
United States
Language:
English