ISSN:
0044-2313
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
On the Knowledge of BaAlF5BaAlF5 occurs in three modifications. The hithertoo little characterized Low Temperature Form (LTF, α-BaAlF5) crystallizes orthorhombic with a = 13.710; b = 5.604; c = 4.930 Å, Z = 4, space group P212121 isotypic with BaGaF5. Single crystal data show that β-BaAlF5 has a monoclinic unit cell with a = 5.148; b = 19.556; c = 7.553 Å, β = 92.43°, Z = 8. The HTF γ-BaAlF5 a = 5.258; b = 9.724; c = 7.366 Å, β = 90.89°, Z = 4, obtained by quenching. Investigations by is monoclinic with DTA and quenching prove that α- transforms slowly and irreversible to β-BaAlF5 starting at 666°C. The reservible transformation β- to γ;BaAlF5 occurs at 789°C.
Notes:
BaAlF5 bildet drei Modifikationen. Die Tieftemperaturform (TTF, α-BaAlF5) kristallisiert orthorhombisch mit a = 13,710; b = 5,604; c = 4,930 Å, Z = 4, Raumgruppe P212121, isotyp mit BaGaF5. Einkristalluntersuchungen an β-BaAlF5 belegen eine monokline Struktur mit a = 5,148; b = 19,556; c = 7,553 Å, β = 92,43°, Z = 8. Die durch Abschrecken der Präparate erhaltene HTF γ-BaAlF5 ist ebenfalls monoklin, a = 5,258; b = 9,724; c = 7,366 Å, β = 90,89°, Z = 4. Nach Temperversuchen und DTA-Messungen wandelt sich α-langsam irreversibel in β-BaAlF5 um. Der Übergang β- in γ-BaAlF5 erfolgt bei 789°C.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19824950103
