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ekatite

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Journal Article
Published: 01 July 2001
European Journal of Mineralogy (2001) 13 (4): 769–777.
...Paul KELLER Abstract Ekatite, ideally (Fe 3+ , Fe 2+ , Zn) 12 (OH) 6 [AsO 3 ] 6 [AsO 3 HOSiO 3 ] 2 , is a new mineral from Tsumeb, Namibia. It is associated with chalcocite and occurs as small sprays of fine needles, up to 2 mm long and less than 0.2 mm in diameter. Ekatite is brownish black...
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Journal Article
Published: 01 October 2012
The Canadian Mineralogist (2012) 50 (5): 1197–1231.
.... Smaller triangular channels contain planar BO 3 groups, while in other materials the triangular channels are occupied by tetrahedral or pyramidal groups. Holtite and magnesiodumortierite are isostructural with dumortierite, while ellenbergerite, phosphoellenbergerite, ekatite, and the synthetic materials...
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<b>Ekatite</b> forming a small spray of fine needles on a matrix of corroded quart...
Published: 01 July 2001
Fig. 1. Ekatite forming a small spray of fine needles on a matrix of corroded quartz.
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Chemical composition of <b>ekatite</b>.
Published: 01 July 2001
Table 1. Chemical composition of ekatite.
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X-ray powder diffraction data for <b>ekatite</b>.
Published: 01 July 2001
Table 2. X-ray powder diffraction data for ekatite.
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Experimental details and crystallographic data for <b>ekatite</b>.
Published: 01 July 2001
Table 3. Experimental details and crystallographic data for ekatite.
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Atomic coordinates and displacement parameters (x10 −4 ) of <b>ekatite</b>.
Published: 01 July 2001
Table 4. Atomic coordinates and displacement parameters (x10 −4 ) of ekatite.
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Crystal structure of <b>ekatite</b> projected onto the (001) plane. The polyhedra ...
Published: 01 July 2001
Fig. 2. Crystal structure of ekatite projected onto the (001) plane. The polyhedra represent the octahedra of M(1)O 4 (OH) 2 and the tetrahedra of HOSi(2)O 3 , which envelop the As(2)O 3 groups. The hexagonal and triangular channels are indicated with I and II, respectively.
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Structural relationships between the <b>ekatite</b> (a) and phosphoellenbergerite ...
Published: 01 July 2001
Fig. 5. Structural relationships between the ekatite (a) and phosphoellenbergerite (b) structure types. The trigonal rods are circled. I and II indicate the hexagonal and triangular channels, respectively. (a). In the hexagonal channel I, the edges of the empty trigonal prisms with As(1
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Selected atomic distances (Å) and angles (°) for <b>ekatite</b>.
Published: 01 July 2001
Table 5. Selected atomic distances (Å) and angles (°) for ekatite.
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Bond valence table for <b>ekatite</b>.
Published: 01 July 2001
Table 6. Bond valence table for ekatite.
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ORTEP drawings of some coordination polyhedra of <b>ekatite</b>: (a) HOSi(2)O 3  a...
Published: 01 July 2001
Fig. 4. ORTEP drawings of some coordination polyhedra of ekatite: (a) HOSi(2)O 3 and (b) As(2)O 3 , both parallel to the c -axis; (c) As(1)O 3 , and the strongly deformed M(1) 2 O 7 (OH) 2 dimer (d), viewed along the c -axis. Whereas OH(5) displays an unusually large isotropic displacement
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Crystal structure of <b>ekatite</b> seen along [001]. A and B indicate a perpendic...
Published: 01 July 2001
Fig. 3. Crystal structure of ekatite seen along [001]. A and B indicate a perpendicular and clinographic view, respectively, on the zigzag double chains of octahedral dimers. The O(5) vertices of the HO(5)Si(2)O(3) 3 tetrahedra all point into the same direction.
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The crystal structure of holtedahlite: a dense packing of II-rods known fro...
Published: 01 July 2001
Fig. 6. The crystal structure of holtedahlite: a dense packing of II-rods known from the ekatite and the phosphoellenbergerite structures. The ordering of M(1) cations of holtedahlite is given as M(1.1) and M(1.2). Note that only one half of the X(1) polyhedra of ekatite occurs in holtedahlite
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The structures of the arsenites with infinite frameworks of Asφ 3  and Mφ 4...
Published: 01 January 2014
Figure 64 The structures of the arsenites with infinite frameworks of Asφ 3 and Mφ 4-6 polyhedra: (a) reinerite, (b) asbecasite, (c) trigonite, (d) tomichite as a member of the derbylite group, (e) ekatite, a perspective view into the tunnels lined by Asφ 3 groups, (f) zimbabweite.
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Unit-cell parameters  a versus c  for DLMs. Sources for naturally occurring...
Published: 01 October 2012
from Brunet et al . (1998) ]; black diamonds, ekatite [from Keller (2001) ]; white hexagons, TM phosphites [2 data from Marcos et al . (1993b) , 2 from Attfield et al . (1994) , 2 from Ni et al . (2009) , and one each from Marcos et al . (1993c) , Che et al . (2005) , Gu et al . (2007
Journal Article
Published: 01 August 2013
Mineralogical Magazine (2013) 77 (6): 2825–2839.
... ) Crystal structure of holtite I . Crystallography Reports , 50 , 42 – 47 . Kazantsev S.S. Zubkova N.V. Voloshin A.V. ( 2006 ) Refinement of composition and structure of holtite I . Crystallography Reports , 51 , 412 – 413 . Keller P. ( 2001 ) Ekatite, (Fe 3...
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Journal Article
Published: 01 April 2014
The Canadian Mineralogist (2014) 52 (2): 121–128.
... ); stanekite ( Keller et al. 1997 ); ekatite ( Keller 2001 ); ferrorosemaryite ( Hatert et al. 2005a ); and joosteite ( Keller et al. 2007 ). The iron and bismuth phosphate from Schneeberg (Erzgebirge, Saxony, Germany) [Bi 2 Fe 3+ (PO 4 )O 2 (OH) 2 ] was named paulkellerite in his honor ( Dunn et al...
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Journal Article
Published: 01 February 2002
The Canadian Mineralogist (2002) 40 (1): 247–254.
...; P alenzona , A. ( 2000 ): Cerchiaraite, a new natural Ba–Mn–mixed-anion silicate chloride from the Cerchiara mine, northern Apennines, Italy. Neues Jahrbuch für Mineralogie, Monatshefte , 373 –384. K eller , P. ( 2001 ): Ekatite, (Fe 3+ ,Fe 2+ ,Zn) 12 (OH) 6 [AsO 3 ] 6 [AsO 3 ,HOSiO 3...
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Journal Article
Published: 01 March 2014
European Journal of Mineralogy (2014) 26 (1): 113–125.
... in the structurally related ekatite ( Keller, 2001 ). Our XAS and EPR spectra show that both As 3+ and As 5+ preferentially occupy the Si site in the borosilicate danburite. Kraisslite, mcgovernite and nelenite of the friedelite group contain still higher amounts of As 3+ and As 5+ ( Dunn & Nelen, 1981...
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