Polymorphism and multiple twinning of (Et4N)2ZnCl4

Sondergeld, P.; Fuess, H.; Ishihara, H. und Schmahl, Wolfgang W. (2001): Polymorphism and multiple twinning of (Et4N)2ZnCl4. In: Zeitschrift fur Kristallographie, Bd. 216, Nr. 8: S. 462-468

Abstract

The phase sequence of (Et4N)2ZnCl4 has been determined based on thermal analysis and 35Cl NQR spectroscopy. On cooling two phase transitions are observed at 223.0(5) and 217.7(9) K, respectively. On heating only one phase transition is found at 228.4(3) K. Therefore three phases are distinguished below the decomposition point (556(5) K) with a metastable phase in the temperature region 217-229 K, a twinned low-temperature phase below and a disordered high-temperature phase above this region, respectively. The structure of the low-temperature phase has been determined from X-ray 4-circle diffraction data. The space group of this phase is C2ca (Aba2) with a = 11.366(6) Å, b = 13.347(4) Å and c = 15.246(6) Å at T = 190 K. From the group-subgroup relations between the high- and the low-temperature phase the structure of the intermediate phase has been derived and confirmed by the analysis of the transition entropies.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften > Kristallographie und Materialwissenschaft
• Themengebiete: 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• Sprache: Englisch