Stützite crystal structure determination

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Marco E. Ciriotti
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Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Stützite crystal structure determination

Messaggio da Marco E. Ciriotti » gio 14 dic, 2017 10:10

Prossima pubblicazione.

Referenza:
▪ Bindi, L. & Keutsch, F.N. (2018): Old defined minerals with complex, still unresolved structures: the case of stützite, Ag5−x Te3. Zeitschrift für Kristallographie - Crystalline Materials, 233, (in press).

Abstract:
The crystal structure of the mineral stützite, a relatively common silver telluride, was solved using intensity data collected using a crystal from the cotype material from the May Day mine, La Plata District, CO (USA). The study revealed that the structure is hexagonal, space group P6̅, with cell parameters: a=13.454(2), c=8.459(1) Å and V=1326.0(5) Å3. The refinement of an anisotropic model led to an R index of 0.0421 for 1950 independent reflections. In the crystal structure of stützite there are eight independent Te sites and eight Ag sites with Z=7. Only Ag5, Ag6, Ag7 and Ag8 form classic metal-anion polyhedra: Ag8 is in linear coordination, Ag5 and Ag6 are triangularly coordinated, whereas Ag7 is in tetrahedral coordination. The case for Ag1, Ag2, Ag3 and Ag4 is more complicated as there are Ag–Ag contacts beside the typical bonds with the chalcogen. These positions correspond to low coordination (two, three and four) sites, in agreement with the silver preference for such environments. d10 silver ion distribution has been evidenced by means of a combination of a Gram-Charlier development of the atomic displacement factors and a split model. A discussion on the possible existence of different polytypes in stützite-like compounds and on the use of the non-harmonic approach based upon a Gram-Charlier development of the atomic displacement factors for the determination of disordered structures is also presented.
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: 24009
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Re: Stützite crystal structure determination

Messaggio da Marco E. Ciriotti » ven 13 apr, 2018 12:45

Pubblicazione effettuata.

Referenza:
▪ Bindi, L. & Keutsch, F.N. (2018): Old defined minerals with complex, still unresolved structures: the case of stützite, Ag5−x Te3. Zeitschrift für Kristallographie - Crystalline Materials, 233, 247-253.
Marco E. Ciriotti

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

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