ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The direct method previously proposed [Hao, Liu & Fan (1987). Acta Cryst. A43, 820-824] has been used to determine the incommensurate modulation in the structure of ankangite by using the h0l electron diffraction pattern. Ankangite is a newly discovered mineral which belongs to the priderite group with chemical composition Ba0.8(Ti, V, Cr)8O16. The h0l electron diffraction pattern shows sharp satellite reflections which correspond to a one-dimensional incommensurate modulation along the c axis. Direct phasing of the h0l satellite reflections based on the known phases of the main reflections led to a three-dimensional hyperprojection along the a2 direction of the four-dimensional electron potential distribution, revealing clearly occupational and positional modulations of the Ba atoms. Positional modulation of other atoms has also been observed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0108767390007607
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