Crystal structure of Pb-exchanged form of zorite

Zubkova, N. V.; Pushcharovsky, D.Y.; Giester, Gerald; Pekov, Igor V.; Turchkova, Anna G.; Тиллманнс, Е.; Чуканов, Н. В.

doi:10.1134/s1063774506030035

Cited by 8 publications

(3 citation statements)

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“…Several alternative OD models for zorite are described by Cruciani et al (1998) and Belokoneva (2005). Due to the use of zorite as a molecular sieve, there has been much work on Pb 2+ -, K + -and Cs + -exchanged forms of zorite (Zubkova et al, 2006.…”

Section: T 4 3 T Ribbonsmentioning

confidence: 99%

A structure hierarchy for silicate minerals: chain, ribbon, and tube silicates

Day

Hawthorne

2020

MinMag

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A structure hierarchy is developed for chain-, ribbon- and tube-silicate based on the connectedness of one-dimensional polymerisations of (TO4)n− tetrahedra, where T = Si4+ plus P5+, V5+, As5+, Al3+, Fe3+, B3+, Be2+, Zn2+ and Mg2+. Such polymerisations are described by a geometrical repeat unit (with ng tetrahedra) and a topological repeat unit (or graph) (with nt vertices). The connectivity of the tetrahedra (vertices) in the geometrical (topological) repeat units is denoted by the expression cTr (cVr) where c is the connectivity (degree) of the tetrahedron (vertex) and r is the number of tetrahedra (vertices) of connectivity (degree) c in the repeat unit. Thus cTr = 1Tr12Tr23Tr34Tr4 (cVr = 1Vr12Vr23Vr34Vr4) represents all possible connectivities (degrees) of tetrahedra (vertices) in the geometrical (topological) repeat units of such one-dimensional polymerisations. We may generate all possible cTr (cVr) expressions for chains (graphs) with tetrahedron (vertex) connectivities (degrees) c = 1 to 4 where r = 1 to n by sequentially increasing the values of c and r, and by ranking them accordingly. The silicate (sensu lato) units of chain-, ribbon- and tube-silicate minerals are identified and associated with the relevant cTr (cVr) symbols. Following description and association with the relevant cTr (cVr) symbols of the silicate units in all chain-, ribbon- and tube-silicate minerals, the minerals are arranged into decreasing O:T ratio from 3.0 to 2.5, an arrangement that reflects their increasing structural connectivity. Considering only the silicate component, the compositional range of the chain-, ribbon- and tube-silicate minerals strongly overlaps that of the sheet-silicate minerals. Of the chain-, ribbon- and tube-silicates and sheet silicates with the same O:T ratio, some have the same cVr symbols (vertex connectivities) but the tetrahedra link to each other in different ways and are topologically different. The abundance of chain-, ribbon- and tube-silicate minerals decreases as O:T decreases from 3.0 to 2.5 whereas the abundance of sheet-silicate minerals increases from O:T = 3.0 to 2.5 and decreases again to O:T = 2.0. Some of the chain-, ribbon- and tube-silicate minerals have more than one distinct silicate unit: (1) vinogradovite, revdite, lintisite (punkaruaivite) and charoite have mixed chains, ribbons and/or tubes; (2) veblenite, yuksporite, miserite and okenite have clusters or sheets in addition to chains, ribbons and tubes. It is apparent that some chain-ribbon-tube topologies are favoured over others as of the ~450 inosilicate minerals, ~375 correspond to only four topologically unique graphs, the other ~75 minerals correspond to ~46 topologically unique graphs.

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Section: T 4 3 T Ribbonsmentioning

confidence: 99%

A structure hierarchy for silicate minerals: chain, ribbon, and tube silicates

Day

Hawthorne

2020

MinMag

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“…It was demonstrated that potassium and sodium titanium silicates efficiently absorb cations of heavy metals (Cs + , Rb + , Pb 2+ , Hg 2+ etc.) from aqueous solutions (Bortun et al, 1999;Zubkova et al, 2005Zubkova et al, , 2006Zubkova et al, , 2007Chukanov et al, 2010;Chukanov, Tarasov et al 2011;Chukanov, Kazakov, Pekov & Grigor'eva, 2011;Chukanov et al, 2012;Popa & Pavel, 2012;Noh et al, 2012;Grigor'eva et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Microporous crystal structure of labuntsovite-Fe and high-pressure behavior up to 23 GPa

Aksenov

Bykova

Расцветаева

et al. 2018

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Labuntsovite-Fe, an Fe-dominant member of the labuntsovite subgroup, was first discovered in the Khibiny alkaline massif on Mt Kukisvumchorr . Zap. Vseross. Mineral. Oba, 130,[36][37][38][39][40][41][42][43][44][45]. However, no data are published about the crystal structure of this mineral. Labuntsovite-Fe from a peralkaline pegmatite located on Mt Nyorkpakhk, in the Khibiny alkaline complex, Kola Peninsula, Russia, has been investigated by means of electron microprobe analyses, single-crystal X-ray structure refinement, and IR and Raman spectroscopies. Monoclinic unit-cell parameters of labuntsovite-Fe are: a = 14.2584 (4), b = 13.7541 (6), c = 7.7770 (2) Å , = 116.893 (3) ; V = 1360.22 (9) Å 3 ; space group C2/m. The structure was refined to final R 1 = 0.0467, wR 2 = 0.0715 for 3202 reflections [I > 3(I)]. The refined crystal chemical formula is (Z = 2): Na 2 K 2 Ba 0.7 [(Fe 0.5 Ti 0.1 Mg 0.05 )(H 2 O) 1.3 ]{[Ti 2 (Ti 1.9 Nb 0.1 )-(O,OH) 4 ][Si 4 O 12 ] 2 }Á4H 2 O.The high-pressure in situ single-crystal X-ray diffraction study of the labuntsovite-Fe has been carried out in a diamond anvil cell. The labuntsovite-type structure is stable up to 23 GPa and phase transitions are not observed. Calculations using the BM3 equation of state resulted in the bulk modulus K = 72 (2) GPa, K 0 0 = 3.7 (2) and V 0 = 1363 (2) Å 3 . Compressing of the heteropolyhedral zeolite-like framework leads to the deformation of main structural units. Octahedral rods show the gradual increase of distortion and the wave-like character of rods becomes more distinct. Rod deformations result in the distortion of the silicon-oxygen ring which is not equal in different directions. Structural channels are characterized by a different ellipticitypressure relationship: the cross-section of the largest channel I and channel II demonstrates the stability of the geometrical characteristics which practically do not depend on pressure: " channel I ' 0.85 (4) (cross-section is rather regular) and " channel II ' 0.52 (2) within the whole pressure range. However, channel III is characterized by the increasing of ellipticity with pressure (" = 0.40 ! 0.10).

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“…The high cation exchange capacity has been also patented for sorbent applications of radioactive Cs and Sr isotopes [12]. Mineral zorite and related ETS-4 structures have attracted significant interest due to their versatile ion exchange properties including elements as Co, Cd, Hg [13], Tl [14], Pb [15], Cs [16], Ca and Ba [17,18]. However, the detailed structural studies of all these works are missing or they are limited to isolated single crystals of the mineral zorite.…”

Section: Introductionmentioning

confidence: 99%