Kalifersite, a new alkaline silicate from Kola Peninsula (Russia) based on a palygorskite-sepiolite polysomatic series

Ferraris, Giovanni; Khomyakov, A. P.; Belluso, Elena; Соболева, С. В.

doi:10.1127/ejm/10/5/0865

Cited by 28 publications

(11 citation statements)

References 8 publications

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“…In Fig. 9d, the six-membered rings in kalifersite ((K,Na) 5 Fe 3+ 7 [Si 20 O 50 ](OH) 6 (H 2 O) 12 ; Ferraris et al, 1998) have the arrangements (u 6 ), (u 3 d 3 ), (d 6 ) and (d 3 u 3 ) in ratios of 2:1:1:1 and a planar unit-cell four times that of the arrangement (u 6 ) ( Fig. 1).…”

Section: U-d Strings and The Relative Orientation Of Tetrahedra In Shmentioning

confidence: 99%

Generating functions for stoichiometry and structure of single- and double-layer sheet-silicates

Hawthorne

2015

Mineral. mag.

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Two-dimensional nets may be used to generate the stoichiometry and structure of single-layer and double-layer sheet-silicate minerals. Many sheet-silicate minerals are based on the 3-connected plane nets 63, 4.82, (4.6.8)2(6.82)1and (52.8)1(5.82)1, and some more complicated nets, e.g. (5.6.7)4(5.72)1(62.7)1, (4.122)2(42.12)1, (52.8)1(5.62)1(5.6.8)2(62.8)1,have one or two representative structures. Many complicated sheet-silicate minerals are based on sheets of 2-, 3- and 4-connected tetrahedra that may be developed from 3- and 4-connected plane nets by a series of oikodoméic operations on 3- or 4-connected nets that change the topologyof the parent net. There are three classes of oikodoméic operations: (1) insertion of 2- and 3-connected vertices into 3- and 4-connected plane nets; (2,3) replication of single-layer sheets by topological mirror or two-fold-rotation operators, and condensation of the resulting twosingle-layer sheets to form double-layer sheets. The topological aspects of these sheet structures may be described by functions that express stoichiometry in terms of tetrahedron connectivities (formula-generating functions) and functions that associate these formula-generating functionswith specific two-dimensional nets. Using these functions, we may generate formulae and structural arrangements of single-layer and double-layer silicate structures with specific local and long-range topological features.

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Section: U-d Strings and The Relative Orientation Of Tetrahedra In Shmentioning

confidence: 99%

Generating functions for stoichiometry and structure of single- and double-layer sheet-silicates

Hawthorne

2015

Mineral. mag.

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“…Heterogeneous anomalous mixed crystals are widespread in nature, especially among layered sili cates [1][2][3]. They are formed both through solid phase topotaxial reactions and by direct crystallization [4].…”

Section: Introductionmentioning

confidence: 99%

Growth kinetics and micromorphology of NH4Cl:Mn2+ crystals formed in the NH4Cl-MnCl2-H2O-CONH3 system

et al. 2012

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The growth kinetics and elementary growth processes on the surface of NH 4 Cl:Mn 2+ heteroge neous crystals formed in the NH 4 Cl-MnCl 2 -H 2 O-CONH 3 system are experimentally studied. It is found that a change in the composition of complexes in an NH 4 Cl crystal from Mn(NH 4 ) 2 Cl 4 · 2H 2 O to MnCl 2 · 2CONH 3 leads to the occurrence of a local maximum in the kinetic curve and a change in the shape of dis location growth centers from flat to conical. The growth kinetics of {100} faces of heterogeneous NH 4 Cl:Mn 2+ crystals is described within the Bliznakov model using the Fowler-Guggenheim adsorption isotherm, which takes into account the lateral interaction of adsorbed particles. Fig. 10. Increase in the (a) height and (b) width of a sharp vertex hillock with time.

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“…The structural unit common to these four minerals is an [M 5 (OH) 2 (T 8 O 20 )] framework, essentially amphibole I-beams that link by sharing tetrahedron corners to form a framework of tetrahedra and octahedra. Palygorskyite forms one end of the palesepiole polysomatic series (Ferraris & Gula 2005), the other end being sepiolite, and various members of this series are known, e.g., kalifertisite (Ferraris et al 1998), together with related minerals, e.g., intersilite (Egorov-Tismenko et al 1996 and raite (Pluth et al 1997). The structures of the other members of the palygorskyite group have been reported (Table 1) and all have significant vacancies at the octahedrally coordinated M sites, suggesting that the formula Mn 5 (Si 8 O 20 )(OH) 2 (H 2 O) 9 generally given for yofortierite may be rather idealistic.…”

Section: Introductionmentioning

confidence: 99%

The Crystal Structure of Yofortierite

Hawthorne

Abdu

Tait

et al. 2013

The Canadian Mineralogist

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The crystal structure of yofortierite, (Mn 2+ ,Mg,Fe 3+ ,o) 5 Si 8 O 20 (OH,H 2 O) 2 (H 2 O) 7 , monoclinic, C2/m, Z = 4, a 14.1686(12), b 17.8583(16), c 5.2919(5) Å, β 105.878(1)°, V 1287.9(3) Å 3 , has been refined to R 1 = 4.9 % for 1795 unique (F o > 4σF) reflections collected on a Bruker D8 three-circle diffractometer equipped with a rotating-anode generator (MoKα X-radiation), a multi-layer optics incident-beam path, and an APEX-II CCD detector. Chemical analysis by electron microprobe plus Fe 3+ determination by Mössbauer spectroscopy gave SiO 2 51.78, Al 2 O 3 0.05, TiO 2 0.15, Fe 2 O 3 1.84, MnO 22.97, ZnO 0.99, MgO 4.32, CaO 1.10, H 2 O calc 16.69, sum 99.89 wt.%. The resulting empirical formula is (Mn 3.01 Mg 1.00 Zn 0.11 Ca 0.18 Fe 3+ 0.21 Ti 0.02 Al 0.01 o 0.46) Σ=5 Si 8.00 O 20 [(OH) 1.34 (H 2 O) 0.66 ] Σ=2 (H 2 O) 7. Yofortierite is a palygorskyite-group mineral. There are two tetrahedrally coordinated T sites occupied by Si with distances of 1.621 and 1.617 Å, and three octahedrally coordinated M sites, occupied primarily by Mn 2+ and Mg with minor Fe 3+ and o, with distances of 2.147, 2.079, and 2.183 Å. The distances indicate strong order of M cations over the three M sites, with the smaller cations and vacancies ordered at the M(2) site and Ca ordered at the M(3) site. The presence of vacancies at the M(2) site locally couple with the replacement of (OH)at the O(4) site by (H 2 O) o , giving rise to strong short-range order, and H 2 O is incorporated into the framework part of the structure by the substitution Mn 2+ + (OH)-= o + (H 2 O) o which is coupled to the substitution Mn 2+ = Fe 3+ by the requirement of electroneutrality.

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Kalifersite, a new alkaline silicate from Kola Peninsula (Russia) based on a palygorskite-sepiolite polysomatic series

Cited by 28 publications

References 8 publications

Generating functions for stoichiometry and structure of single- and double-layer sheet-silicates

Generating functions for stoichiometry and structure of single- and double-layer sheet-silicates

Growth kinetics and micromorphology of NH4Cl:Mn2+ crystals formed in the NH4Cl-MnCl2-H2O-CONH3 system

The Crystal Structure of Yofortierite

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