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Crystal chemistry of zemannite-type structures: II. Synthetic sodium zemannite
journal contribution
posted on 2023-05-21, 15:50 authored by Owen MissenOwen Missen, Mills, SJ, Spratt, JNew zemannite-type phases, from Na 1.25 Fe 0.75 3 + Zn 1.25 ( Te O 3 ) 3 ∙ 3 H 2 O to Na 0.55 Fe 1.44 3 + Zn 0.56 ( Te O 3 ) 3 ∙ 3 H 2 O have been synthesised hydrothermally under basic conditions from a mixture of tellurium dioxide, zinc oxide, and either iron (III) oxide or iron (III) nitrate nonahydrate. Analysis by electron microprobe and inductively coupled plasma atomic emission spectrometry showed considerable variation in the Fe(III) and Zn contents of the framework. Single crystals of the compound produced from the iron (III) oxide syntheses were analysed, showing lower unit-cell parameters than natural zemannite, with a = 9.2620(9) and c = 7.6148(7) Å. The structure differs from type zemannite by the presence of Na and a water molecule which bridges the channel and framework by bonding via the oxygen atom. The unit-cell parameters of the compounds produced from iron (III) nitrate nonahydrate syntheses were refined from powder data and shown to increase with increasing pH. The results of this study show the potential for solid solution to exist in natural zemannite-type minerals and gives a stable boundary for the formation of pure zemannite-type compounds at basic pH levels, between pH 11.5 and pH 14.
History
Publication title
European Journal of MineralogyVolume
31Pagination
529 - 536ISSN
1617-4011Department/School
School of Natural SciencesPublisher
Copernicus GmbHPlace of publication
GermanyRights statement
Copyright 2019 E. Schweizerbart’sche Verlagsbuchhandlung, 70176 Stuttgart, GermanyRepository Status
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