Se-rich canfieldite from the Shuangjianzishan Ag-Pb-Zn deposit, NE China: multimethodic chemical and structural study

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Marco E. Ciriotti
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Se-rich canfieldite from the Shuangjianzishan Ag-Pb-Zn deposit, NE China: multimethodic chemical and structural study

Messaggio da Marco E. Ciriotti » mar 09 ott, 2018 9:59

Prossima pubblicazione.

Referenza:
▪ Zhai, D., Bindi, L., Voudouris, P.C., Liu, J., Tombros, S.F., Li, K. (2019): Discovery of Se-rich canfieldite, Ag8Sn(S,Se)6, from the Shuangjianzishan Ag-Pb-Zn deposit, NE China: A multimethodic chemical and structural study. Mineralogical Magazine, 83, (in press).

NdR: Impossibile proporre l'abstract nel modo usuale. L'uso della tastiera cinese comporta enormi distorsioni nel copia-incolla. L'unico modo è mediante una foto (vedi allegato).
Canfieldite Se-rich abstract.doc
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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: 31645
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Re: Se-rich canfieldite from the Shuangjianzishan Ag-Pb-Zn deposit, NE China: multimethodic chemical and structural stud

Messaggio da Marco E. Ciriotti » mar 04 giu, 2019 16:12

Ora l'abstract è proponibile.

Referenza:
▪ Zhai, D., Bindi, L., Voudouris, P.C., Liu, J., Tombros, S.F., Li, K. (2019): Discovery of Se-rich canfieldite, Ag8Sn(S,Se)6, from the Shuangjianzishan Ag-Pb-Zn deposit, NE China: A multimethodic chemical and structural study. Mineralogical Magazine, 83, (in press).

Abstract:
During a study of the ore minerals belonging to the recently discovered Shuangjianzishan Ag–Pb–Zn deposit in NE China, we have discovered exceptional selenium enrichment in canfieldite (up to 11.6 wt.% of Se). Incorporation of Se into canfieldite has been investigated by an integrated approach using field emission scanning electron microscopy, electron microprobe and single-crystal X-ray diffraction. Canfieldite has been identified as one of the dominant Ag-bearing ore minerals in the studied deposit, which occurs mostly in slate-hosted vein type Ag–Pb–Zn ore bodies. Selenium is either homogeneously or, remarkably, heterogeneously distributed in the different canfieldite fragments studied. Chemical variations of Se are mostly attributable to a series of retrograde reactions resulting in diverse decomposition and exsolution of primary phases during cooling, or alternatively, related to influxes of Se-rich fluids during the formation of canfieldite. To evaluate the effects of the Se-for-S substitution in the structure, a crystal of Se-rich canfieldite [Ag7.98Sn1.02(S4.19Se1.81)Σ6.00] was investigated. The unit-cell parameters are: a = 10.8145(8) Å and V = 1264.8(3) Å3. The structure was refined in the space group F 3m to R1 = 0.0315 for 194 independent reflections, with 20 parameters. The crystal structure of Se-rich canfieldite was found to be topologically identical to that of pure canfieldite. If the short Ag–Ag contacts are ignored (due to the disorder), the two Ag atoms in the structure can be considered as three-fold (Ag1) and four-fold (Ag2) coordinated. Tin adopts a regular tetrahedral coordination. As in the case of Te-rich canfieldite, the refinement of the site-occupancy factor indicates that Se is disordered over the three anion positions.
Marco E. Ciriotti

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