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Structural studies of schultenite in the temperature range 125–324 K by pulsed single crystal neutron diffraction — hydrogen ordering and structural distortions

Published online by Cambridge University Press:  05 July 2018

C. C. Wilson
C. C. Wilson*
Affiliation:
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX 11 OQX, UK
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Abstract

The structure of the mineral schultenite, PbHAsO4, has been studied using pulsed neutron single crystal diffraction. The low-temperature, low-symmetry structure is found to exhibit substantial ordering of the hydrogen atom onto one of two possible sites, which are equally occupied in the high-temperature phase above 313 K. The occupancies found at low temperature agree well with the normal behaviour for such a hydrogen ordering phase transition in this type of material. In addition the heavy atom lattice distortion has been characterised as a function of temperature and found to follow broadly the pattern of hydrogen ordering. Higher-temperature measurements at and above the phase transition confirm the high symmetry nature of the structure in this region, with no significant distortions from this within the resolution of the present data.

Keywords

hydrogen orderingpulsed single crystal neutron diffractionphase transitionschultenite
Type
Mineralogy
Information
Mineralogical Magazine , Volume 58 , Issue 393 , December 1994 , pp. 629 - 634
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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