The crystal structures of (NH4)2TeBr6 and Ce2TeBr6 have been
reinvestigated using X-ray diffraction from powders and single crystals.
Three dimensional single crystal intensity data obtained photographically
have been used to refine these structures, which are of the cubic K2PtCl6
type, by a full matrix least squares analysis. The Te-Br bond is found
to be 2.70* in both crystals after correction for the thermal notion of
the atoms.
A phase transition in (NH4)2TeBr6 has been observed at about
183°K. Pros an examination of Weissenberg photographs taken at 163°K,
the low temperature phase is found to be tetragonal, space group p4/mnc
(D64h) with a « 7.501+/-0.005* and c =10.765*+/-0.005*. The transformation
in this case is probably similar to that reported in other isomorphous
crystals, e.g., K2snBr6.
A review of other crystals with similar structure is included
in this thesis and the theory of X-ray diffraction as applicable to the
present problem is discussed briefly. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/29151 |
| Date | 05 1900 |
| Creators | Das, Ajit Kumar |
| Contributors | Brown, I. D., Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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