Tumchaite Na2(Zr,Sn)Si4O11·2H2O—A new mineral from carbonatites of the Vuoriyarvi alkali-ultrabasic massif, Murmansk Region, Russia

Subbotin, V. V.; Merlino, Stefano; Pushcharovsky, Dmitry Yu.; Pakhomovsky, Yakov A.; Ferro, O.; Bogdanova, A. N.; Voloshin, A. V.; Sorokhtina, N. V.; Zubkova, N. V.

doi:10.2138/am-2000-1024

Cited by 23 publications

(8 citation statements)

References 6 publications

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“…Elpidite, gaidonnayite, hilairite and catapleiite are all unbranched chain silicates (Liebau 1985) with differing periodicities or chain topologies (elpidite, gaidonnayite, hilairite versus the silicate ring in catapleiite). Tumchaite (Subbotin et al 2000) is also unbranched, but is classified as a sheet silicate, whereas natrolemoynite is classified as loop-branched silicate. The crystal structures of both tumchaite and natrolemoynite are characterized by higher Si:O ratios, relative to those of more simple unbranched silicates (Table 6).…”

Section: Description and Discussion Of The Structurementioning

confidence: 99%

Natrolemoynite, a New Hydrated Sodium Zirconosilicate From Mont Saint-Hilaire, Quebec: Description and Structure Determination

McDonald

Chao

2001

The Canadian Mineralogist

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Natrolemoynite is a new member of the lemoynite group found in altered or unaltered pegmatites cutting nepheline syenite at the Poudrette quarry, Mont Saint-Hilaire, Quebec. In altered pegmatites, it is associated with microcline, lemoynite, lepidocrocite, galena, sphalerite, calcite and pyrite, and in unaltered pegmatites, with biotite, microcline, albite, magnetite, a chlorite-group mineral, a burbankite-group mineral, an unidentified donnayite-(Y)-like mineral, zircon and pyrochlore. Crystals are colorless to white (occasionally with a slightly pink to red tinge), bladed to prismatic, elongate along [001], with maximum widths of 1 mm and lengths of 2 mm. The mineral typically develops in compact radial aggregates and spheres 4 mm in maximum diameter. It is transparent to translucent, with a vitreous to subadamantine luster and a white streak. The Mohs hardness is 3. Perfect {100} and {010} cleavages and a poor {001} cleavage are observed. D meas is 2.47(1) g/cm 3 and D calc , 2.50 g/cm 3. Natrolemoynite is biaxial negative, ␣ 1.533(1), ␤ 1.559(1), ␥ 1.567(1), 2V meas. = 63(1)°, 2V calc. = 57(1)°; dispersion is weak, with r and v crossed. The optical orientation is X = b, Z ٙ a = 41° (measured in the obtuse angle ␤). The average result of nineteen electron-microprobe analyses gave Na 2 O 7.47, K 2 O 1.29, CaO 0.37, MnO 0.12, Al 2 O 3 0.04, SiO 2 54.51, TiO 2 0.38, ZrO 2 21.97, Nb 2 O 5 1.01 and H 2 O (calc.) 14.72, total 101.88 wt.%, corresponding to (Na 2.66 K 0.30 Ca 0.07 Mn 0.02) ⌺3.05 (Zr 1.96 Nb 0.08 Ti 0.05) ⌺2.09 (Si 9.99 Al 0.01) ⌺10 O 25.79 • 9H 2 O on the basis of 10(Si + Al) or, ideally, Na 4 Zr 2 Si 10 O 26 •9H 2 O. It is monoclinic, C2/m, a 10.5150(2), b 16.2534(4), c 9.1029(3) Å, ␤ 105.462(2)°, V 1499.4(1) Å 3 , Z = 2. The structure was refined to R = 4.2% for 2133 reflections [F o > 4(F o)]. Six-membered rings of SiO 4 tetrahedra are linked along [001] by ZrO 6 octahedra to form a zirconosilicate framework. Channels parallel to [001] are occupied by Na and H 2 O. Evidence is provided for limited Na ↔ H 3 O + substitution. Crystal-chemical and field relations indicate that paragenetically, natrolemoynite is one of the last sodium zirconosilicate hydrate phases to develop.

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Section: Description and Discussion Of The Structurementioning

confidence: 99%

Natrolemoynite, a New Hydrated Sodium Zirconosilicate From Mont Saint-Hilaire, Quebec: Description and Structure Determination

McDonald

Chao

2001

The Canadian Mineralogist

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“…Fig. 15c) and the net of tetrahedra in tumchaite, Na 2 (Zr,Sn)Si 4 O 11 (H 2 O) 2 (Subbotin et al, 2000). The net corresponding to the sheet of tetrahedra (Fig.…”

Section: Insertion Of 2-connected Vertices Into 3-connected Plane Netsmentioning

confidence: 99%

“…Consider the structures of tumchaite, Na 2 (Zr, Sn)Si 4 O 11 (H 2 O) 2 (Subbotin et al, 2000), and zeophyllite (Merlino, 1972;Mikenda et al, 1997), both of which are single-layer sheet-silicate minerals based on the (6 3 ) 2 net with inserted 2-connected vertices (Figs 18 and 19). The net in tumchaite is (10 2 ) 1 (10 3 ) 1 (Fig.…”

Section: Fig 29mentioning

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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“…Two dimensional anionic tetrahedral ribbonlike structures with the same formula [Si 4 O 11 ] ∞ are characteristic of amphiboles and vlasovite. Layered anionic radicals [Si 4 O 11 ] ∞∞ are the basis of the crystal structure of min erals such as penkvilskite [19] and tumchaite [20].…”

Section: Ray Experiments and Structure Refinementmentioning

confidence: 99%

Crystal structure of magnesioneptunite

Karimova

Yakubovich

Zadov³

et al. 2012

Crystallogr. Rep.

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The crystal structure of the new mineral magnesioneptunite (K 0.8 Na 0.1 ᮀ 0.1 )Na 2 Li(Ti 0.39 Mg 0.34 Fe 0.27 ) 2 (Ti 0.59 Mg 0.22 Fe 0.19 ) 2 [Si 4 O 11 ] 2 (O,OH) from the xenolith of Verkhneche gemskaya caldera (Lakarga Mountain, North Caucasus) has been investigated by X ray diffraction (XCali bur S diffractometer, R = 0.0244): a = 16.3271 (7) Å, b = 12.4788(4) Å, c = 9.9666(4) Å, β = 115.651(5), V = 1830.5(1) Å 3 , sp. gr. C2/c, Z = 4, and ρ calcd = 3.152 g/cm 3 . The disordered distribution of Ti, Mg, and Fe atoms in the octahedra forming the basis of the cationic framework is established. It is shown that the isomor phic occupation of octahedral positions by cations of three types corresponds to the centrosymmetric crystal structure and is likely caused by the high temperature crystallization of the mineral.

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Tumchaite Na₂(Zr,Sn)Si₄O₁₁·2H₂O—A new mineral from carbonatites of the Vuoriyarvi alkali-ultrabasic massif, Murmansk Region, Russia

Cited by 23 publications

References 6 publications

Natrolemoynite, a New Hydrated Sodium Zirconosilicate From Mont Saint-Hilaire, Quebec: Description and Structure Determination

Natrolemoynite, a New Hydrated Sodium Zirconosilicate From Mont Saint-Hilaire, Quebec: Description and Structure Determination

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

Crystal structure of magnesioneptunite

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