The crystal structure of aluminium hexaurea perchlorate, Al(urea)6(ClO4)3, at room temperature and its relation to the phase transition at 25°C
✍ Scribed by J.H.M. Mooy; W. Krieger; D. Heijdenrijk; C.H. Stam
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 372 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Crystals of Al(urea)6(C10~)3 are rhombohedral at room temperature with space group R% 2nd hexagonal ceIL constants c = 18.087 and c = 13.980 A. The crystal structure ai room temperature has been determined. It is isomorphous with that ofTi(ureaj6(C10q)a and eshibits the same sort of disorder for the Cl04 grokps. This disorder is interpreted in terms of two dispositions of the Cl04 groups connected by tviofold LYXCS of the space ~oup.,'D.e rehtion of the room temperature siructurc with the phase transition at about 25°C is discussed in conneciion with ESR results, Ir is shown that the actual symmetry of the structure above the transition is R3 rather than R3c