期刊
JOURNAL OF SOLID STATE CHEMISTRY
卷 178, 期 5, 页码 1376-1385出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jssc.2004.12.037
关键词
perovskite; methylammonium lead chloride; phase transition; neutron and synchrotron powder diffraction; rietveld refinement
The perovskite-structured compound methylammonium lead chloride orders into a low-temperature phase of space group Pnma, in which at 80 K each of the orthorhombic axes a = 11.1747(2) angstrom, b = 11.3552(1) angstrom, and c = 11.2820(1) angstrom is doubled with respect to the room temperature disordered cubic phase (a = 5.669 angstrom). The structure was solved by ab initio methods using the programs EXPO and FOX. This unusual cell basis for space group Pnma is not that of a standard tilt system. This phase, in which the methylammonium ions, are ordered shows distorted octahedra. The octahedra possess a bond angle variance of 60.663(degrees 2) and a quadratic elongation of 1.018, and are more distorted than those in the ordered phase of methylammonium lead bromide. There is also an alternating long and short Pb-Cl bond along a, due to an off-center displacement of Pb within the octahedron. This suggests that the most rigid unit is actually the methylammonium cation, rather than the PbCl6 octahedra, in agreement with existing spectroscopic data. Crown Copyright (c) 2005 Published by Elsevier Inc. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据