Hydration, structure, and superconductivity of KOs2O6·nH2O

Rosa Galati; Charles Simon; Christopher S. Knee; Paul F. Henry; Brian D. Rainford; Mark T. Weller

doi:10.1021/cm702972c

Hydration, structure, and superconductivity of KOs₂O₆·nH₂O

Rosa Galati, Charles Simon, Christopher S. Knee, Paul F. Henry, Brian D. Rainford, Mark T. Weller

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

10 Citations (SciVal)

Abstract

In moist air or by contact with water during washing, KOs2O6 absorbs water molecules into the structure to produce KOs2O6·nH2O, 0 < n < 0.1. This water is reversibly lost on heating above 430 K in flowing or static gas environments. Variable temperature powder neutron and X-ray diffraction show that an increase in lattice parameter occurs when water enters the pyrochlore structure and the water molecules are located in the α cages displacing a portion of the potassium ions to adjacent sites. On removing water the lattice parameter and structure revert to those of the normal β-pyrochlore crystallographic description. Hydration has the effect of reducing the onset of superconducting behavior from a critical temperature of 10.25 K in fully dry KOs2O6 to 9.75 K in KOs2O6·0.1H2O.

Original language	English
Pages (from-to)	1652-1659
Number of pages	8
Journal	Chemistry of Materials
Volume	20
Issue number	4
Early online date	19 Jan 2008
DOIs	https://doi.org/10.1021/cm702972c
Publication status	Published - 26 Feb 2008

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abstract = "In moist air or by contact with water during washing, KOs2O6 absorbs water molecules into the structure to produce KOs2O6·nH2O, 0 < n < 0.1. This water is reversibly lost on heating above 430 K in flowing or static gas environments. Variable temperature powder neutron and X-ray diffraction show that an increase in lattice parameter occurs when water enters the pyrochlore structure and the water molecules are located in the α cages displacing a portion of the potassium ions to adjacent sites. On removing water the lattice parameter and structure revert to those of the normal β-pyrochlore crystallographic description. Hydration has the effect of reducing the onset of superconducting behavior from a critical temperature of 10.25 K in fully dry KOs2O6 to 9.75 K in KOs2O6·0.1H2O.",

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T1 - Hydration, structure, and superconductivity of KOs2O6·nH2O

AU - Galati, Rosa

AU - Simon, Charles

AU - Knee, Christopher S.

AU - Henry, Paul F.

AU - Rainford, Brian D.

AU - Weller, Mark T.

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N2 - In moist air or by contact with water during washing, KOs2O6 absorbs water molecules into the structure to produce KOs2O6·nH2O, 0 < n < 0.1. This water is reversibly lost on heating above 430 K in flowing or static gas environments. Variable temperature powder neutron and X-ray diffraction show that an increase in lattice parameter occurs when water enters the pyrochlore structure and the water molecules are located in the α cages displacing a portion of the potassium ions to adjacent sites. On removing water the lattice parameter and structure revert to those of the normal β-pyrochlore crystallographic description. Hydration has the effect of reducing the onset of superconducting behavior from a critical temperature of 10.25 K in fully dry KOs2O6 to 9.75 K in KOs2O6·0.1H2O.

AB - In moist air or by contact with water during washing, KOs2O6 absorbs water molecules into the structure to produce KOs2O6·nH2O, 0 < n < 0.1. This water is reversibly lost on heating above 430 K in flowing or static gas environments. Variable temperature powder neutron and X-ray diffraction show that an increase in lattice parameter occurs when water enters the pyrochlore structure and the water molecules are located in the α cages displacing a portion of the potassium ions to adjacent sites. On removing water the lattice parameter and structure revert to those of the normal β-pyrochlore crystallographic description. Hydration has the effect of reducing the onset of superconducting behavior from a critical temperature of 10.25 K in fully dry KOs2O6 to 9.75 K in KOs2O6·0.1H2O.

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Hydration, structure, and superconductivity of KOs₂O₆·nH₂O

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