Crystal chemistry of julgoldite: Re-investigation of Fe distribution and hydrogen-bonding

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Marco E. Ciriotti
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Crystal chemistry of julgoldite: Re-investigation of Fe distribution and hydrogen-bonding

Messaggio da Marco E. Ciriotti » ven 02 mar, 2018 11:31

Prossima pubblicazione.

Referenza:
▪ Nagashima, M., Cametti, G., Armbruster, T. (2018): Crystal chemistry of julgoldite, a mineral series of the pumpellyite group: Re-investigation of Fe distribution and hydrogen-bonding. European Journal of Mineralogy, 30, (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: 24900
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 chemistry of julgoldite: Re-investigation of Fe distribution and hydrogen-bonding

Messaggio da Marco E. Ciriotti » sab 09 giu, 2018 15:24

Referenza:
▪ Nagashima, M., Cametti, G., Armbruster, T. (2018): Crystal chemistry of julgoldite, a mineral series of the pumpellyite group: Re-investigation of Fe distribution and hydrogen-bonding. European Journal of Mineralogy, 30, (in press).

Abstract:
Single-crystal X-ray crystal-structure refinements and electron-microprobe analyses of two julgoldite samples, in one case complemented by Mössbauer spectroscopy to determine the Fe valence distribution, yielded the compositions Ca2.00X(Fe2+0.44Fe3+0.29Mg0.17Al0.10)Y(Fe3+0.82Al0.18)2Si3O10.39(OH)3.61 (Bombay) and Ca2.00X(Fe0.67Mg0.16Al0.17)Y(Fe3+0.81Al0.19)2Si3O14 − n(OH)n (4 ≥ n ≥ 3) (Kreimbach/Kaulbach), respectively. Structure refinements also allowed specification of the system of hydrogen bonds, which concur with those known for pumpellyite. A review of structural and chemical data for pumpellyite-group minerals including six julgoldite samples indicated that the length of the b axis is governed by the average size of ionic radii at the Y site, except for one sample of julgoldite-(Fe3+). Size effects of the concentration of “large” divalent cations (Mg, Fe) at the X site can be seen in the lateral extension of the (010) plane that acts as a buffer to accomodate the variable size of the X octahedra. Using unit-cell plots, the data suggest that five of the six tested julgoldite samples are julgoldite-(Fe2+) and only the one sample of the Bombay area studied by Artioli et al. (2003) is julgoldite-(Fe3+). Both samples studied in this paper were classified into julgoldite-(Fe2+). In contrast to pumpellyite samples sensu stricto, which exhibit a Me2+:Me3+ ratio of approximately 1:1, julgoldite samples may cover the whole range between Ca2X(Fe3+)Y(Fe3+)2Si3O11(OH)3 and Ca2X(Fe2+)Y(Fe3+)2Si3O10(OH)4.
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: 24900
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Crystal chemistry of julgoldite: Re-investigation of Fe distribution and hydrogen-bonding

Messaggio da Marco E. Ciriotti » mer 17 ott, 2018 18:41

Pubblicazione effettuata:

Referenza:
▪ Nagashima, M., Cametti, G., Armbruster, T. (2018): Crystal chemistry of julgoldite, a mineral series of the pumpellyite group: Re-investigation of Fe distribution and hydrogen-bonding. European Journal of Mineralogy, 30, 721-731.
Marco E. Ciriotti

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

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