Zeolitic water in strunzite-group minerals

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Marco E. Ciriotti
Messaggi: 24934
Iscritto il: ven 25 giu, 2004 11:31
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Zeolitic water in strunzite-group minerals

Messaggio da Marco E. Ciriotti » mar 11 lug, 2017 9:41

Prossima pubblicazione.

Referenza:
▪ Grey, I.E. & Kampf, A.R. (2018): Zeolitic water in strunzite-group minerals. Mineralogical Magazine, 82, (in press).

Abstract:
The crystal structures have been refined for the first time for the strunzite-group minerals ferristrunzite and ferrostrunzite. Structure refinements are also presented for strunzite from three different localities. A common feature of all refined structural models is the presence of zeolitic water in the interlayer region, displaced by 0.4-0.5 Å from an inversion centre at (½ 0 ½). The refined occupancy of the site ranged from 44% to 100% in the samples studied. H-bonding associated with the zeolitic water causes large displacements, up to 0.7 Å, of neighbouring coordinated water molecules, relative to the structure with no zeolitic water. A new formula is proposed for strunzite-group minerals with divalent interlayer cations as M2+Fe3+2(PO4)2(OH)2·(6.5-x)H2O; M = Mn, Fe, Zn and 0 < x < 0.5 accounts for varying degrees of dehydration. For ferristrunzite and other potential strunzite-group members with trivalent cations in the interlayer octahedron, the formula is M3+Fe3+2(PO4)2(OH)3·(5.5-x)H2O.

Strunzite group
Ferristrunzite Fe3+Fe3+2(PO4)2(OH)2(H2O)6.32
Ferrostrunzite Fe2+Fe3+2(PO4)2(OH)3(H2O)5.5
Strunzite Mn2+Fe3+2(PO4)2(OH)2(H2O)6.33
Zincostrunzite ZnFe3+2(PO4)2(OH)2(H2O)6
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: 24934
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Zeolitic water in strunzite-group minerals

Messaggio da Marco E. Ciriotti » mer 04 lug, 2018 9:20

Pubblicazione effettuata.

Referenza:
▪ Grey, I.E. & Kampf, A.R. (2018): Zeolitic water in strunzite-group minerals. Mineralogical Magazine, 82, 291-299.

Abstract:
The crystal structures have been refined for the first time for the strunzite-group minerals ferristrunzite and ferrostrunzite. Structure refinements are also presented for strunzite from three different localities. A common feature of all refined structural models is the presence of zeolitic water in the interlayer region, displaced by 0.4-0.5 Å from an inversion centre at (½ 0 ½). The refined occupancy of the site ranged from 44% to 100% in the samples studied. H-bonding associated with the zeolitic water causes large displacements, up to 0.7 Å, of neighbouring coordinated water molecules, relative to the structure with no zeolitic water. A new formula is proposed for strunzite-group minerals with divalent interlayer cations as M2+Fe3+2(PO4)2(OH)2·(6.5-x)H2O; M = Mn, Fe, Zn and 0 < x < 0.5 accounts for varying degrees of dehydration. For ferristrunzite and other potential strunzite-group members with trivalent cations in the interlayer octahedron, the formula is M3+Fe3+2(PO4)2(OH)3·(5.5-x)H2O.
Marco E. Ciriotti

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

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