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Crystal structure of tetra­wickmanite, Mn(2+)Sn(4+)(OH)(6)

The crystal structure of tetra­wickmanite, ideally Mn(2+)Sn(4+)(OH)(6) [mangan­ese(II) tin(IV) hexa­hydroxide], has been determined based on single-crystal X-ray diffraction data collected from a natural sample from Långban, Sweden. Tetra­wickmanite belongs to the octa­hedral-framework group of hydr...

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Detalles Bibliográficos
Autores principales: Lafuente, Barbara, Yang, Hexiong, Downs, Robert T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384573/
https://www.ncbi.nlm.nih.gov/pubmed/25878828
http://dx.doi.org/10.1107/S2056989015001632
Descripción
Sumario:The crystal structure of tetra­wickmanite, ideally Mn(2+)Sn(4+)(OH)(6) [mangan­ese(II) tin(IV) hexa­hydroxide], has been determined based on single-crystal X-ray diffraction data collected from a natural sample from Långban, Sweden. Tetra­wickmanite belongs to the octa­hedral-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 ABO(3) 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. Tetra­wickmanite exhibits tetra­gonal symmetry and is topologically similar to its cubic polymorph, wickmanite. The tetra­wickmanite structure is characterized by a framework of alternating corner-linked [Mn(2+)(OH)(6)] and [Sn(4+)(OH)(6)] octa­hedra, 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 octa­hedra 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 tetra­gonal stottite, Fe(2+)Ge(4+)(OH)(6).