| | 1 | Author
| M. Arietta, S. Schriewer-Pöttgen, Wolfgang Jeitschko | Requires cookie* | | | Title
| Two Modifications of Hg5Re2O 10  | | | | Abstract
| The previously reported mercury perrhenate Hg5 Re2O 10, prepared hydrothermally, has now been obtained by reaction of HgO with the mercury(II) metaperrhenate H g (R e 0 4)2 in sealed silica tubes. A second modification o f this compound can be obtained by reaction of elem ental mercury with H g (R e 0 4)2 also in sealed silica tubes. Its crystal structure has been determined from single-crystal X-ray data: P 2 x/c, a -861.5(1), b = 1200.9(2), c = 1203.9(2) pm, ß = 97.15(1)°, Z = 4, R = 0.024 for 1733 structure factors and 105 variables. Both modifi cations may be represented by the formula H g2+-2H g20 -2 R e 0 4_, indicating that mercury occurs in oxidation states I and II. In both modifications the mercury and some oxygen atoms form two-dimensionally infinte, puckered, cationic nets of the composition (H g2+-2H g20)" , which are separated by the R e 0 4~ tetrahedra. In the modification reported earlier the mer cury oxygen nets consist of condensed 16-membered rings, while the nets of the present modification contain 10-and 22-membered rings. | | | |
Reference
| Z. Naturforsch. 50b, 1335—1339 (1995); received February 27 1995 | | | |
Published
| 1995 | | | |
Keywords
| Crystal Structure, Mercury Perrhenates, Phase Transitions | | | |
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| default:Reihe_B/50/ZNB-1995-50b-1335.pdf | | | | Identifier
| ZNB-1995-50b-1335 | | | | Volume
| 50 | |
| 2 | Author
| Marcos Luján, Frank Kubel, Hans Schmid | Requires cookie* | | | Title
| Crystal Growth, Room Temperature Crystal Structure and Phase Transitions of K M nP04 | | | | Abstract
| Single crystals of K M nP 04 grown in a KC1 flux show ferroelastic domains. The structure was determ ined on an optically controlled single domain crystal by X-ray diffraction methods. The cell is triclinic with dimensions a = 5.4813(5), b = 8.627(1), c = 8.887(1), in A, a = 87.73(1)°, ß = 89.10(1)°, y = 88.01(1)°, VM = 419.6(1) A 3 and Z = 4. The structure is closely related to the stuffed /3-tridymite type. DTA experiments between room tem perature and 1000 °C and polarized light microscopy observations showed four phase transitions: at 165, 330, 353 and 707 °C. | | | |
Reference
| Z. Naturforsch. 50b, 1210—1214 (1995); received February 20 1995 | | | |
Published
| 1995 | | | |
Keywords
| Manganese Potassium Orthophosphate, Crystal Structure, Crystal Growth, Phase Transitions | | | |
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| default:Reihe_B/50/ZNB-1995-50b-1210.pdf | | | | Identifier
| ZNB-1995-50b-1210 | | | | Volume
| 50 | |
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