Refinement of the crystal structure of schneiderhöhnite

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Marco E. Ciriotti
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Refinement of the crystal structure of schneiderhöhnite

Messaggio da Marco E. Ciriotti » mer 22 mar, 2017 19:16

Prossima pubblicazione.

Referenza:
▪ Cooper, M.A. & Hawthorne, F.C. (2016): Refinement of the crystal structure of schneiderhöhnite. Canadian Mineralogist, 54, (in press).
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 23421
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Re: Refinement of the crystal structure of schneiderhöhnite

Messaggio da Marco E. Ciriotti » mer 05 apr, 2017 8:34

Pubblicazione effettuata.

Referenza:
▪ Cooper, M.A. & Hawthorne, F.C. (2016): Refinement of the crystal structure of schneiderhöhnite. Canadian Mineralogist, 54, 707-713.

Abstract:
The crystal structure of schneiderhöhnite, Fe2+Fe3+3As3+5O13, triclinic P-1, a 8.945(3), b 10.022(3), c 9.161(4) Å, α 62.942(5), β 116.072(6), γ 81.722(6)°, has been refined to an R1 value of 1.4%. The structure is very close to that reported by Hawthorne (1985), but detailed examination of the structural connectivity shows that schneiderhöhnite is better described as a sheet structure than as a framework structure. Zig-zag chains of edge-sharing Fe(1), Fe(2), Fe(3) (= Fe3+) octahedra extend parallel to the c axis, and these chains are cross-linked into a corrugated sheet by tetramers of edge-sharing Fe(4) (= Fe3+) and Fe(5) (= Fe2+) octahedra. (As3+O3) triangular pyramids decorate the surface of this sheet of octahedra as single (AsO3) groups, with all three short bonds linked to anion vertices of the octahedra, and as two crystallographically distinct [As2O5] dimers with four short bonds (two from each As3+) to octahedron vertices. The sheets are connected along [100] via the bridging anion of one of the two [As2O5] dimers that bonds to an Fe2+ octahedron of the adjacent sheet, imparting a strong sheet-like character to the structure and accounting for the perfect (100) cleavage.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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