Crystal structure of veenite

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Marco E. Ciriotti
Messaggi: 23485
Iscritto il: ven 25 giu, 2004 11:31
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Crystal structure of veenite

Messaggio da Marco E. Ciriotti » mar 23 ago, 2016 15:33

Prossima pubblicazione.

Referenza:
▪ Topa, D. & Makovicky, E. (2017): The crystal structure of veenite. Mineralogical Magazine, 81, (in press).

Abstract:
The crystal structure of veenite is reported for the first time from a sample from the type locality of Madoc (Ontario, Canada). It has been solved and refined by X-ray single-crystal diffraction on the basis of 4973 observed reflections (with Fo > 4σ(Fo)) with a final R1 =0.0396. Veenite is monoclinic P21, with unit-cell parameters a = 8.429(2), b = 26.069(5), c = 8.962(2) Å, β = 117.447(2)o. The bulk veenite composition is Ag0.15Pb16.029Sb8.836As6.99S39.95 (for Z = 1) corresponding to N = 4.09 (Me8NS8N+8, theoretical value is 4.0), with the percentage of the Ag- (As,Sb) substituted end-member equal only to 3.51 mol %, i.e., a nearly pure Pb-Sb-As sulfosalt. The crystal structure is typical for the N = 4 sartorite homologue, with zig-zag walls of trigonal coordination prisms of Pb which separate slabs of diagonally oriented double-layers populated by Sb and As with partial Pb substitution. Orientation of three-membered crankshaft chains formed by strong (As,Sb) – S bonds on the two surfaces of double-layers differs substantially from that in dufrénoysite, which is a pure Pb-As (N = 4) sulfosalt.
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: 23485
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Re: Crystal structure of veenite

Messaggio da Marco E. Ciriotti » gio 30 mar, 2017 10:52

Pubblicazione effettuata.

Referenza:
▪ Topa, D. & Makovicky, E. (2017): The crystal structure of veenite. Mineralogical Magazine, 81, 355–368.
Marco E. Ciriotti

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

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