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A Pressure‐Induced Phase Transformation in a UO 3 Monohydrate
Author(s) -
HARRIS L. A.,
TAYLOR A. J.
Publication year - 1962
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1962.tb11023.x
Subject(s) - orthorhombic crystal system , phase (matter) , crystallography , materials science , lath , transformation (genetics) , diffusionless transformation , chemistry , crystal structure , martensite , microstructure , biochemistry , organic chemistry , gene
An orthorhombic dipyramidal form and an orthorhombic lath‐shaped form of UO 3 monohydrate were grown hydrothermally. Optical and X‐ray constants were determined for these crystalline modifications. The X‐ray data corroborated previous data reported by Zachariasen for the orthorhombic laths and by Dawson et al . for the dipyramidal form. An unreported phase transformation was observed to take place in the orthorhombic dipyramidal phase on the application of pressure. Optical and X‐ray examinations of the new phase showed it to be identical to the orthorhombic lath phase. The transformation appeared to fit Buerger's “displacive transformation” classification. Optical observations made on partly transformed dipyramidal crystals lying on their (001) faces showed the two phases, i.e., the dipyramidal phase and the new phase, joined along a (11.l) dipyramid plane. The displacive movement appeared to have taken place in a (110) dipyramid direction.