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Crystal Structure, Phase Transition and Ferroelastic Properties of [N(CH 3 ) 4 ] 3 [As 2 Cl 9 ]
Author(s) -
Wojtaś M.,
Bator G.,
Ciunik Z.
Publication year - 2004
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200300276
Subject(s) - tetramethylammonium , phase transition , crystal structure , crystallography , crystal (programming language) , phase (matter) , relaxation (psychology) , dielectric , atmospheric temperature range , chemistry , trigonal crystal system , ferroelectricity , space group , x ray crystallography , materials science , ion , condensed matter physics , diffraction , physics , optics , thermodynamics , social psychology , psychology , optoelectronics , organic chemistry , computer science , programming language
The crystal structure of [N(CH 3 ) 4 ] 3 [As 2 Cl 9 ] is determined at 293 K. It crystallizes in trigonal space group P31c: a = 9.2199(8), c = 21.065(3)Å, Z = 2, R 1 = 0.0505, wR 2 = 0.1283. The crystal is built of the discrete bioctahedral [As 2 Cl 9 ] 3— anions and the deformed tetramethylammonium cations. A structural phase transition in [N(CH 3 ) 4 ] 3 [As 2 Cl 9 ] is detected by the DSC and dilatometric techniques at 146/151 K (on cooling/heating). Dielectric relaxation studies in the frequency range 75 kHz — 5 MHz indicate reorientations of the tetramethylammonium cations within the high temperature phase. Optical observations show the existence of the ferroelastic domain structure below 146 K. The possible mechanism of phase transition is discussed on the basis of the presented results.