Studies of layered uranium(VI) compounds. IV. Proton conductivity in single-crystal hydrogen uranyl phosphate tetrahydrate (HUP) and in polycrystalline hydrogen uranyl arsenate tetrahydrate (HUAs)

Journal Article · Mon Sep 01 04:00:00 EDT 1980 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(80)90217-0· OSTI ID:6873023

Howe, A T; Shilton, M G

Single-crystal measurements on hydrogen uranyl phosphate tetrahydrate, HUO/sub 2/PO/sub 4/.4H/sub 2/O (HUP), have confirmed that the high proton conductivity is a bulk characteristic. The conductivity values were in substantial agreement with those previously reported for polycrystalline disks. A conductivity of 0.6 ohm/sup -1/ m/sup -1/ at 290/sup 0/K and an activation energy of 30 +- 1 kJ mole/sup -1/ were measured parallel to the structural layers of the crystal. The conductivity was at least 100 times lower when measured in the perpendicular direction. A reasonable attempt frequency ..omega../sub 0/ of approximately 10/sup 15/ Hz could be derived from the parallel conductivity on the assumption that the charge carrier concentration was equal to that of the H/sub 3/O/sup +/ ions. This implies a low proton mobility, of the order of 10/sup -9/ m/sup 2/ V/sup -1/ sec/sup -1/ at 290/sup 0/K, in support of previous estimates. We have also shown that polycrystalline hydrogen uranyl arsenate tetrahydrate, HUO/sub 2/AsO/sub 4/.4H/sub 2/O (HUAs), has a high conductivity of 0.6 ohm/sup -1/ cm/sup -1/ at 310/sup 0/K, with an activation energy of 31 +- 2 kJ mole/sup -1/. Below the respective dielectric ordering transition temperatures of HUP and HUAs of 274 and 301/sup 0/K, the lower conductivity values show a marked frequency dependence, which may be due to dispersion effects caused by water reorientations.

• Research Organization: Univ. of Leeds, England
• OSTI ID: 6873023
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 34:2; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPOUNDS
ACTIVATION ENERGY
ARSENATES
ARSENIC COMPOUNDS
CATIONS
CHARGED PARTICLES
CRYSTALS
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ENERGY
HYDRATES
HYDROGEN
HYDROGEN COMPOUNDS
IONS
LAYERS
MEDIUM TEMPERATURE
MOLECULAR IONS
NONMETALS
OXONIUM IONS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
POLYCRYSTALS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
URANIUM COMPOUNDS
URANYL COMPOUNDS
URANYL PHOSPHATES
WATER