Stöger, B., Göb, C., & Topa, D. (2023). A fresh view on the structure and twinning of owyheeite, a rod-polytype and twofold superstructure. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 79(4), 271–280. https://doi.org/10.1107/S2052520623004523
E057-04 - Fachbereich Röntgenzentrum E057 - Facilities und Zentren
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Zeitschrift:
Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
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Datum (veröffentlicht):
1-Aug-2023
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Umfang:
10
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Verlag:
INT UNION CRYSTALLOGRAPHY
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Peer Reviewed:
Ja
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Keywords:
mineral; polytypism; superstructure; twinning; OD theory
en
Abstract:
Owyheeite [Cu0.09 (1)Ag2.77 (4)Pb10.23 (4)Sb10.89 (5)S28.00 (5)] crystallizes as a twofold superstructure with P21/n symmetry and pseudo-orthorhombic metrics [a = 8.1882 (3) Å, b = 27.2641 (7) Å, c = 22.8679 (7) Å, β = 90.293 (3)°, V = 5105.0 (3) Å3, Z = 4]. Owyheeite is systematically twinned by reflection at (021) or equivalently (021). Twinning is explained by describing a simplified Pmcn archetype structure as polytype built of two kinds of rods, which contact via electron-pair micelles. A procedure of generating hypothetical polytypes by tiling space with partially overlapping equivalent regions is described.
