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Crystal structure of tetra-wickmanite, Mn(2+)Sn(4+)(OH)6.

Lafuente B, Yang H, Downs RT - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: The vacant A site is in a cavity in the centre of a distorted cube formed by eight octa-hedra at the corners.However, the hydrogen-atom positions and their hydrogen bonds are not equivalent in every cavity, resulting in two distinct environments.One of the cavities contains a ring of four hydrogen bonds, similar to that found in wickmanite, while the other cavity is more distorted and forms crankshaft-type chains of hydrogen bonds, as previously proposed for tetra-gonal stottite, Fe(2+)Ge(4+)(OH)6.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA.

ABSTRACT
The crystal structure of tetra-wickmanite, ideally Mn(2+)Sn(4+)(OH)6 [mangan-ese(II) tin(IV) hexa-hydroxide], has been determined based on single-crystal X-ray diffraction data collected from a natural sample from Långban, Sweden. Tetra-wickmanite belongs to the octa-hedral-framework group of hydroxide-perovskite minerals, described by the general formula BB'(OH)6 with a perovskite derivative structure. The structure differs from that of an ABO3 perovskite in that the A site is empty while each O atom is bonded to an H atom. The perovskite B-type cations split into ordered B and B' sites, which are occupied by Mn(2+) and Sn(4+), respectively. Tetra-wickmanite exhibits tetra-gonal symmetry and is topologically similar to its cubic polymorph, wickmanite. The tetra-wickmanite structure is characterized by a framework of alternating corner-linked [Mn(2+)(OH)6] and [Sn(4+)(OH)6] octa-hedra, both with point-group symmetry -1. Four of the five distinct H atoms in the structure are statistically disordered. The vacant A site is in a cavity in the centre of a distorted cube formed by eight octa-hedra at the corners. However, the hydrogen-atom positions and their hydrogen bonds are not equivalent in every cavity, resulting in two distinct environments. One of the cavities contains a ring of four hydrogen bonds, similar to that found in wickmanite, while the other cavity is more distorted and forms crankshaft-type chains of hydrogen bonds, as previously proposed for tetra-gonal stottite, Fe(2+)Ge(4+)(OH)6.

No MeSH data available.


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Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1). At the top right, the spectral deconvolution obtained with seven fitting peaks using pseudo-Voigt line profiles.
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fig4: Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1). At the top right, the spectral deconvolution obtained with seven fitting peaks using pseudo-Voigt line profiles.

Mentions: The Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1) is displayed in Fig. 4 ▸. The minimum number of peaks needed to fit the spectrum in this region (using pseudo-Voigt line profiles) is seven, which is in agreement with the number of hydrogen bonds derived from the structure (Table 1 ▸). According to the correlation of O—H stretching frequencies and O—H⋯O hydrogen-bond lengths in minerals by Libowitzky (1999 ▸), the most intense peaks (3062, 3145, 3253 and 3374 cm−1) are within the range of calculated wavenumbers for the H⋯O distances between 2.75 and 2.86 Å and they correspond to the strongest hydrogen bonds in the structure.


Crystal structure of tetra-wickmanite, Mn(2+)Sn(4+)(OH)6.

Lafuente B, Yang H, Downs RT - Acta Crystallogr E Crystallogr Commun (2015)

Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1). At the top right, the spectral deconvolution obtained with seven fitting peaks using pseudo-Voigt line profiles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384573&req=5

fig4: Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1). At the top right, the spectral deconvolution obtained with seven fitting peaks using pseudo-Voigt line profiles.
Mentions: The Raman spectrum of tetra­wickmanite in the OH-stretching region (2800–3900 cm−1) is displayed in Fig. 4 ▸. The minimum number of peaks needed to fit the spectrum in this region (using pseudo-Voigt line profiles) is seven, which is in agreement with the number of hydrogen bonds derived from the structure (Table 1 ▸). According to the correlation of O—H stretching frequencies and O—H⋯O hydrogen-bond lengths in minerals by Libowitzky (1999 ▸), the most intense peaks (3062, 3145, 3253 and 3374 cm−1) are within the range of calculated wavenumbers for the H⋯O distances between 2.75 and 2.86 Å and they correspond to the strongest hydrogen bonds in the structure.

Bottom Line: The vacant A site is in a cavity in the centre of a distorted cube formed by eight octa-hedra at the corners.However, the hydrogen-atom positions and their hydrogen bonds are not equivalent in every cavity, resulting in two distinct environments.One of the cavities contains a ring of four hydrogen bonds, similar to that found in wickmanite, while the other cavity is more distorted and forms crankshaft-type chains of hydrogen bonds, as previously proposed for tetra-gonal stottite, Fe(2+)Ge(4+)(OH)6.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA.

ABSTRACT
The crystal structure of tetra-wickmanite, ideally Mn(2+)Sn(4+)(OH)6 [mangan-ese(II) tin(IV) hexa-hydroxide], has been determined based on single-crystal X-ray diffraction data collected from a natural sample from Långban, Sweden. Tetra-wickmanite belongs to the octa-hedral-framework group of hydroxide-perovskite minerals, described by the general formula BB'(OH)6 with a perovskite derivative structure. The structure differs from that of an ABO3 perovskite in that the A site is empty while each O atom is bonded to an H atom. The perovskite B-type cations split into ordered B and B' sites, which are occupied by Mn(2+) and Sn(4+), respectively. Tetra-wickmanite exhibits tetra-gonal symmetry and is topologically similar to its cubic polymorph, wickmanite. The tetra-wickmanite structure is characterized by a framework of alternating corner-linked [Mn(2+)(OH)6] and [Sn(4+)(OH)6] octa-hedra, both with point-group symmetry -1. Four of the five distinct H atoms in the structure are statistically disordered. The vacant A site is in a cavity in the centre of a distorted cube formed by eight octa-hedra at the corners. However, the hydrogen-atom positions and their hydrogen bonds are not equivalent in every cavity, resulting in two distinct environments. One of the cavities contains a ring of four hydrogen bonds, similar to that found in wickmanite, while the other cavity is more distorted and forms crankshaft-type chains of hydrogen bonds, as previously proposed for tetra-gonal stottite, Fe(2+)Ge(4+)(OH)6.

No MeSH data available.


Related in: MedlinePlus