Structure and crystal chemistry of vernadite in ferromanganese crusts

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Marco E. Ciriotti
Messaggi: 25818
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Structure and crystal chemistry of vernadite in ferromanganese crusts

Messaggio da Marco E. Ciriotti » sab 15 giu, 2019 9:42

Referenza:
▪ Lee, S., Xu, H., Xu, W., Sun, X. (2019): The structure and crystal chemistry of vernadite in ferromanganese crusts. Acta Crystallographica, B75, (in press).

Abstract:
Vernadite from ferromanganese crusts has mixed layered structures based on results from synchrotron X-ray diffraction, X-ray pair distribution function, and high-resolution transmission electron microscopy.

_cell_length_a 4.9520(60)
_cell_length_b 2.8330(40)
_cell_length_c 7.2000(200)
_cell_angle_alpha 90.0000(0)
_cell_angle_beta 97.3000(2000)
_cell_angle_gamma 90.0000(0)

_symmetry_space_group_name_H-M C2/m
_symmetry_cell_setting monoclinic
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: 25818
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Structure and crystal chemistry of vernadite in ferromanganese crusts

Messaggio da Marco E. Ciriotti » lun 12 ago, 2019 12:41

Pubblicazione effettuata.

Referenza:
▪ Lee, S., Xu, H., Xu, W., Sun, X. (2019): The structure and crystal chemistry of vernadite in ferromanganese crusts. Acta Crystallographica, B75, 591-598.

Abstract:
The structure and crystal chemistry of vernadite in ferromanganese crusts from the Magellan Seamount in the north‐west Pacific Ocean have been investigated using synchrotron X‐ray diffraction (XRD), X‐ray pair distribution function (PDF) and high‐resolution transmission electron microscopy (TEM). XRD patterns of vernadite mainly show two strong diffraction peaks at 2.42–2.43 Å and 1.41 Å without or with a broad (001) diffraction peak, indicating thin layer nanophases along the c‐direction. TEM images show flat and curved sheet‐like nanocrystals with (001) layer thickness of ∼7.2 Å and ∼9.6 Å, and their interstratified structure. PDF patterns of the vernadite are similar to those from synthetic δ‐MnO2 and defective birnessite, suggesting a phyllomanganate framework. Combined XRD/PDF patterns suggest that vernadite in the outer part is associated with a higher density interlayer species at triple‐edge sharing sites. The proportion of the 10 Å phase increases from the outer (young) part to the inner (old) part of the Mn crusts due to aging and sorption of Mn, Co and Ni from ambient seawater. This study suggests that this combined method of synchrotron radiation XRD/PDF and high‐resolution TEM is a powerful tool to determine atomic structures of poorly crystallized nano‐minerals. The mixture model of vernadite structure will help to understand the partitioning and distribution of trace elements in the ferromanganese crusts.
Marco E. Ciriotti

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