Synthesis,Magnetism, and Crystal Structure of Li2Fe[(PO4)(HPO4)] and its Hydrogen Position Refinement |
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| Authors: | Jin-Xiao Mi Horst Borrmann Hui Zhang Ya-Xi Huang Walter Schnelle Jing-Tai Zhao Prof Dr Rüdiger Kniep |
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| Institution: | 1. Xiamen/P. R. China, Xiamen University, College of Chemistry and Chemical Engineering;2. Dresden/Germany, Max-Planck-Institut für Chemische Physik fester Stoffe;3. Shanghai/P. R. China, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Phone: 86((0)21)-5241-2073, Fax: 86((0)21)-5241-3122 |
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| Abstract: | Lithium iron(III) monophosphate-monohydrogen-monophosphate, Li2Fe(PO4)(HPO4)], was synthesized under mild hydrothermal conditions and its crystal structure was determined by single crystal X-ray diffraction methods. Crystallographic data: monoclinic, P121/n1 (no. 14), a = 4.8142(2) Å, b = 7.9898(4) Å, c = 7.4868(4) Å, β = 104.398(3)°, V = 278.93(2) Å3, Z = 2, Dx = 3.104 g · cm-3. The structure is characterized by FeO6 octahedra sharing common O-corners with six neighbouring PO4 tetrahedra to form a three-dimensional framework. Lithium cations are located within channels running along 100]. The channels are formed by eight-membered rings resulting from the connection of alternating FeO6 octahedra (4×) and phosphate tetrahedra (4×). High-resolution diffraction data allowed to refine a split model for the position of the hydrogen atom. Magnetization data confirm the valence state 3+ for iron and detect an antiferromagnetic ordering of the iron moments below 23.6 K. Thermal decomposition of the compound was investigated by DTA/TG methods. |
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| Keywords: | Hydrogen disorder Iron phosphate Hydrothermal synthesis Crystal structure Magnetic properties |
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