STRUCTURAL STUDY OF TETRAGONAL-ORTHORHOMBIC PHASE-TRANSITION IN NH4SCN

被引：13

作者：

HAMADA, A ^{[1
]}

YAMAMOTO, S ^{[1
]}

SHINNAKA, Y ^{[1
]}

机构：

[1] YAMAGUCHI UNIV,FAC SCI,DEPT PHYS,YAMAGUCHI 753,JAPAN

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 1990年 / 59卷 / 03期

关键词：

ammonium thiocyanate; crystal structure; diffuse scattering; NH4SCN; phase transition;

D O I：

10.1143/JPSJ.59.954

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The crystal structures of NH4SCN are determined in the tetragonal phase I (122°C) and the orthorhombic phase II (100°C, 110°C and 115°C) from X-ray diffraction data. In phase I, SCN- ion is in disordered state taking two equivalent configurations. In phase II, the ordering of SCN- ion correlates to the spontaneous displacement of NH4+ ion. X-ray critical diffuse scattering is observed at the Z-point of the Brillouin-zone boundary in phase I and critical temperature is determined to be 117°C. The I-II phase transition is explained by a coupling system between the orien-tational disorder and the phonon. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

引用

页码：954 / 958

页数：5

共 9 条

[1]

[Anonymous], 1974, INT TABLES XRAY CRYS, VIV

[2] THERMODYNAMIC STUDIES ON PHASE-TRANSITIONS OF POTASSIUM THIOCYANATE AND AMMONIUM THIOCYANATE CRYSTALS [J].