CRYSTAL STRUCTURE OF SYNTHETIC VOLTAITE (K0.90(NH4)0.10)2(Fe3,1902+Fe1,1243+Mg1,686)(Fe0,9383+Mg0,062)2(Al0,98Fe0,023+)(SO4)12x18.9H2O
V. Kh. Sabirov
Ayezov South Kazakhstan State University, Shymkent, Kazakhstan
Keywords: вольтаит, каркасная структура, изовалентное и гетеровалентное замещения, октаэдрическая координация, voltaite, framework structure, isovalent and heterovalent substitutions, octahedral coordination
Abstract
Voltaite of the composition [K0.90(NH4)0.10]2(Fe3,1902+Fe1,1243+Mg1,686)(Fe0,9383+Mg0,062)2(Al0,98Fe0,023+)×(SO4)12x18.9H2O is obtained by treating a polymetallic sample with sulfuric acid. The crystal structure of the substance is formed of (Fe3+,Mg)O6 and (Fe2+,Fe3+,Mg)O4(H2O)2 octahedra and a (K+,NH4+)O12x12-vertex polyhedron arranged in a three-dimensional framework due to the bridging function of the SO42- ion. In the framework voids, [(Fe3+,Al)(H2O)6]3+ cations with aqua ligands disordered over several positions are located.
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