H. Larsen, G. Thorkildsen, D. Nicholson
Dec 1, 2016
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Influential Citations
7
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Journal
Crystal Research and Technology
Abstract
The crystal structures of silver(I) sulphate, Ag2SO4, have been investigated as a function of temperature. A main feature is the phase transition from the low‐temperature ordered phase, F ddd, to the high‐temperature disordered phase, P63/mmc . In particular, the high‐temperature structure is solved from single crystal synchrotron X‐ray measurements. In this phase the title compound undergoes a colossal (anisotropic) thermal expansion of 136(4)×10−6K−1 . This is presumably owing to a high anisotropic vibration state of one of the two crystallographically independent Ag‐atoms. Simultaneously occurring high ionic conductivity may be associated with silver ions moving along the c ‐axis using a “paddle‐wheel” assisted percolative mechanism. Onset of metallic silver in the single crystals is documented, seemingly dependent on thermal pre‐history, mosaic structure and chemical synthesis. Possible mechanisms explaining this effect, comprising disproportionation or photo‐decomposition, are suggested.