Phase transition in C8H20IN. 2CH4N2S

Autor: Tomoyuki Hikita, Yutaka Tsunashima, S. Sato, H. Ishigami, Minoru Sumita
Rok vydání: 2001
Předmět:
Zdroj: Ferroelectrics. 261:257-262
ISSN: 1563-5112
0015-0193
DOI: 10.1080/00150190108216294
Popis: The crystal of the title compound undergoes a phase transition at 288K. Structure determinations were made at 296K and 153K. The structure at room temperature belongs to orthorhombic system with the space group Ibca; the low temperature phase is orthorhombic Pccb. Both phase are centric and Z=8. Large differences of the cell dimensions were not found between both phases. The structure consists of the tetraethylammonium cations, iodide anions and thiourea molecules. No short contacts other than van der Waals ones are observed. The main difference between both structures is that the cations show a disordered arrangement at room temperature whereas they are ordered in the low-temperature phase. The disordered cation statistically occupies two sites relating the two-fold rotation axis with one-half occupancies each.
Databáze: OpenAIRE