A new isomorph of ferrous chloride tetrahydrate: A ⁵⁷Fe Mössbauer and X-ray crystallography study

详细信息    查看全文

• 作者：James N. Bull ; Robert G.A.R. Maclagan ; Christopher M. Fitchett ; W. Craighead Tennant
• 关键词：A. Inorganic compounds ; C. Ab initio calculations ; C. Mö ; ssbauer spectroscopy ; C. X-ray diffraction ; D. Lattice dynamics
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：71
• 期：12
• 页码：1746-1753
• 全文大小：540 K

文摘

This paper outlines the discovery of a newly characterised isomorph of ferrous chloride tetrahydrate, Fe(H₂O)₆·FeCl₄(H₂O)₂, which was initially identified by X-ray crystallography and confirmed by Mössbauer spectroscopy. The X-ray analysis identified the space group as P2₁/c with essentially the same unit cell dimensions as the well-known isomorph, FeCl₂·4H₂O, except that one edge is doubled due to two discrete [Fe(H₂O)₆]²⁺ and [FeCl₄(H₂O)₂]²⁻ species per unit cell. Time-series Mössbauer studies revealed this new isomorph to be unstable upon atmospheric exposure, decaying to the well-known structure over a period of days. Density functional theory calculations support an energetically favourable catalytic interconversion involving adsorbed water. A high-precision redetermination on the FeCl₂·4H₂O crystal structure, which is also in space group P2₁/c, is also reported, providing the unit cell parameters: a=5.8765(3) Å, b=7.1100(3) Å, c=8.4892(5) Å and β=111.096(1)°.