Data di Pubblicazione:
1999
Citazione:
Crystal structure of kanemite, NaHSi2O5.3H(2)O, from the Aris phonolite, Namibia / L. Garvie, B. Devouard, T. Groy, F. Cámara, P.R. Buseck. - In: AMERICAN MINERALOGIST. - ISSN 0003-004X. - 84:(1999), pp. 1170-1175. [10.2138/am-1999-7-820]
Abstract:
Kanemite was studied by single-crystal X-ray diffraction. The mineral, ideally NaHSi 2 O 5 .3H 2 O, is orthorhombic (space group Pbcn); unit-cell parameters are a = 4.946(3), b = 20.502(15), c = 7.275(3) Aa, with Z = 4. The structure is solved and refined to an R value of 0.058 for 825 independent reflections. The arrangement of atoms consists of alternating (010) sheets of corrugated [Si 2 O 4 OH] (super n-) n and hydrated Na. The silicate sheets contain six-membered rings of HOSiO 3 -SiO 4 units. Sodium atoms coordinate to six water molecules, forming layers of distorted octahedra. Residual electron densities were located that give reasonable positions for four H atoms. One H is part of a silanol group, and the other three H atoms are associated with water bonded to Na. Bonding between the silicate and Na sheets is through hydrogen bonding from H of the Na layer to O of the silicate sheet.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
kanemite; single crystal X-ray diffraction; crystal structure; Aris (Namibia); phonolite; EMPA
Elenco autori:
L. Garvie, B. Devouard, T. Groy, F. Cámara, P.R. Buseck
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