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Single‐Crystal Structure and Electronic Conductivity of Melt Synthesized Fe‐rich, near End‐Member Ferro‐Kinoshitalite
Author(s) -
Daab Matthias,
Loch Patrick,
Milius Wolfgang,
SchönauerKamin Daniela,
Schubert Michaela,
Wunder Anja,
Moos Ralf,
Wagner Friedrich E.,
Breu Josef
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700265
Subject(s) - octahedron , crystallography , valence (chemistry) , conductivity , ferrous , materials science , mica , crystal structure , single crystal , electronic structure , electrical resistivity and conductivity , chemistry , mineralogy , metallurgy , computational chemistry , physics , organic chemistry , quantum mechanics
In an attempt to improve the electronic conductivity an Fe II ‐rich brittle mica, a near end‐member Ferro‐Kinoshitalite (BaFe 3 Si 2 Al 2 O 10 F 2 ) was synthesized via a melt approach. The structure is of 1M polytype [ a = 5.4013(11) Å, b = 9.3659(19) Å, c = 9.987(2) Å, β = 100.52(3)°, C 2/ m ] and the iron content clearly exceeds natural abundance levels. The crystal structure is discussed with respect to established limits of isomorphous substitution based on geometrical considerations and is compared to other iron‐rich micas. It is evidenced that the limitation of octahedral Fe II substitution in micas is not merely governed by the misfit of tetrahedral and octahedral sheets as indicated in the literature. The electronic conductivity of contacted single crystals (μS · cm –1 ) is comparable to the conductivity of Ferrous‐Tainiolite and is unfortunately not enhanced by the increased iron content. It is determined by the valence state of Fe rather than by the total Fe content.