ISSN:
1600-5368
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The crystal structure of the rare mixed-valence manganese(II,III) arsenate mineral flinkite [dimanganese(II) manganese(III) arsenate tetrahydroxide], Mn_2^{II}II2MnIII(OH)4(AsO4) has been redetermined from single-crystal X-ray data. The previously unknown positions of both H atoms could be identified. Flinkite contains one unique MnIIIO2(OH)4 polyhedron with a Jahn–Teller-distorted [4+2]-coordination of MnIII, one MnIIO3(OH)3 octahedron, and one fairly regular AsO4 tetrahedron. Atoms on special sites are Mn1 (site symmetry \overline 1), As, O4 and O5 (all with site symmetry .m.). The structure is based upon pyrochroite [Mn(OH)2]-type sheets of edge-sharing Mn(O,OH)6 octahedra parallel to (100). Some Mn(O,OH)6 octahedra are omitted to allow AsO4 tetrahedra to connect the sheets via shared corners. Additional strong hydrogen bonds between the sheets provide further strengthening. Relations to the structures of antlerite, Cu3(SO4)(OH)4, synthetic Cu3(SeO4)(OH)4, synthetic Cu3(CrO4)(OH)4, and szenicsite, Cu3(MoO4)(OH)4, are pointed out.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S1600536801020050
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