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The formation and structure of delta alumina

Published online by Cambridge University Press:  14 March 2018

H. P. Rooksby  and
C. J. M. Rooymans
H. P. Rooksby
Affiliation:
The General Electric Company Ltd., Hirst Research Centre, Wembley, England
C. J. M. Rooymans
Affiliation:
Philips Research Laboratories, Eindhoven, Netherlands
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Abstract

Delta alumina is a transition form obtained during the conversion of boehmite to corundum. Alternative methods have been found for preparing this alumina in a well crystallised condition, enabling detailed X-ray powder data to be compiled. The X-ray data are accounted for by a large tetragonal structure cell of which the axial ratio is 1·47, or 3/2 times the axial ratio of the spinel-like pseudo-cell of Saalfeld. The lattice parameters are a0=7·96 Å and c0=11·70 Å. This large cell provides an integral number of vacancies, contrasting with the 2⅔ vacancies of the pseudo-cell, and allows the atomic arrangement to be ordered.

Type
Research Article
Information
Clay Minerals Bulletin , Volume 4 , Issue 25 , July 1961 , pp. 234 - 238
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1961

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References

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