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X-Ray Powder Diffraction Data and Unit Cells of Ammonium Paratungstate Tetrahydrate

Published online by Cambridge University Press:  10 January 2013

John W. van Put
Affiliation:
Department of Raw Materials Technology, Delft University of Technology, Mijnbouwstraat 120, 2628 RX Delft, The Netherlands
Theo W. Verkroost
Affiliation:
Department of Raw Materials Technology, Delft University of Technology, Mijnbouwstraat 120, 2628 RX Delft, The Netherlands
Eduard J. Sonneveld
Affiliation:
Technisch Physische Dienst TNO-TH, Stieltjesweg 1, 2628 CK Delft, The Netherlands

Abstract

X-Ray powder diffraction data and unit cell parameters of industrially produced, as well as bench scale prepared, ammonium paratungstate tetrahydrate are reported and compared with current Powder Data File (PDF) (1989) patterns. A least-squares refinement resulted in two slightly different unit cells. Both cells are monoclinic with S.G. = P21/n(14), Z = 2. The density, 4.639(2)kg/m3, calculated from one of these unit cells corresponds reasonably well with a measured value of 4.61 (2). It has, however, not been possible to determine at present why ammonium paratungstate tetrahydrate has two unit cells. No relation between the crystalline form and the method of preparation nor the exact water content could be established.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1990

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