A Structural Model of the Layer Titanosilicate Bornemanite Based on Seidozerite and Lomonosovite Modules

Ferraris, Giovanni; Belluso, Elena; Gula, Angela; Соболева, С. В.; Ageeva, Olga; Borutskii, B. E.

doi:10.2113/gscanmin.39.6.1665

Cited by 16 publications

(13 citation statements)

References 12 publications

(9 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The latter I-centred cell corresponds to the orthorhombic (Men'shikov et al, 1975) and monoclinic (Ferraris et al, 2001) I-centred cells previously reported for bornemanite. Note that all three angles in the triclinic I cell are close to but not equal to 90º.…”

Section: The Chemical Formula Of Bornemanitesupporting

confidence: 51%

“…Ferraris et al (2001) reported monoclinic symmetry, a = 5.498, b = 7.120, c = 47.95 Å , g = 88.1º, V = 1876 Å 3 , space group I11b. Our work indicates the triclinic symmetry, a = 5.4587, b = 7.1421, c = 24.528 Å , a = 96.790, b = 96.927, g = 90.326º, V = 942.4 Å 3 , space group P1.…”

Section: The Chemical Formula Of Bornemanitementioning

confidence: 99%

“…Hence, bornemanite belongs to Group III and the TS block has to exhibit linkage 1 and the stereochemistry of Group III: Ti occurs in both the H and O sheets, and two (Si 2 O 7 ) groups link to trans edges of a Ti octahedron in the O sheet. In the bornemanite model of Ferraris et al (2001), the TS block has linkage 3, as in Group IV where Ti equals 4 a.p.f.u. Sokolova (2006) considered the proposed model of the crystal structure of bornemanite extremely unlikely, and suggested that this issue should be reexamined.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

From structure topology to chemical composition. VI. Titanium silicates: the crystal structure and crystal chemistry of bornemanite, a group III Ti-disilicate mineral

Cámara¹,

Sokolova²

2007

Mineral. mag.

View full text Add to dashboard Cite

The crystal structure of bornemanite, ideally Na 6 &BaTi 2 Nb(Si 2 O 7 ) 2 (PO 4 )O 2 (OH)F, a = 5.4587(3), b = 7.1421(5), c = 24.528(2) Å , a = 96.790(1), b = 96.927(1), g = 90.326(1)º, V = 942.4(2) Å 3 , space group P1, Z = 2, D calc. = 3.342 g cm À3 , from the Lovozero alkaline massif, Kola Peninsula, Russia, has been solved and refined to R 1 = 6.36% on the basis of 4414 unique reflections (F o >4sF). Electron microprobe analysis yielded the empirical formula (Na 6 .0 7 Mn 2 + 0 . 2 3 Ca 0 .0 6 & 0 . 6 4 ) S 7 . 0 0 . The crystal structure of bornemanite is a combination of a TS (titanium silicate) block and an I (intermediate) block. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). The TS block exhibits linkage and stereochemistry typical for Group III (Ti = 3 a.p.f.u.) of Ti-disilicate minerals: two H sheets connect to the O sheet such that two (Si 2 O 7 ) groups link to the trans edges of a Ti octahedron of the O sheet. The O sheet cations give Na 3 Ti (4 a.p.f.u.). The TS block has two different H sheets, H 1 and H 2 , where (Si 2 O 7 ) groups link to [5] Ti and [6] Nb polyhedra, and there are two peripheral sites which are occupied by Ba and Na, respectively. There are two I blocks: the I 1 block is a layer of Ba atoms; the I 2 block consists of Na polyhedra and (PO 4 ) tetrahedra.

show abstract

Section: The Chemical Formula Of Bornemanitesupporting

confidence: 51%

Section: The Chemical Formula Of Bornemanitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

From structure topology to chemical composition. VI. Titanium silicates: the crystal structure and crystal chemistry of bornemanite, a group III Ti-disilicate mineral

Cámara¹,

Sokolova²

2007

Mineral. mag.

View full text Add to dashboard Cite

show abstract

“…As for bornemanite (Ferraris et al 2001), kalifersite (Ferraris et al 1998), nafertisite (Ferraris et al 1996), and tungusite (Ferraris et al 1995), the concepts of modular mineralogy (Merlino 1997, Ferraris et al 2004 have been applied to obtain a model of the structure of seidite-(Ce) by comparing chemical composition, cell parameters and diffraction features of the unknown structure with the corresponding quantities of the fully characterized mineral miserite (Scott 1976). Qualitative application of the concepts of modular crystallography has been very effective in modeling the structure of the new titanosilicate seidite-(Ce).…”

Section: Discussionmentioning

confidence: 99%

THE CRYSTAL STRUCTURE OF SEIDITE-(Ce), Na4(Ce,Sr)2 (O,OH,F)4{middle dot}5H2O, A MODULAR MICROPOROUS TITANOSILICATE OF THE RHODESITE GROUP

Ferraris

Belluso

Gula

et al. 2003

The Canadian Mineralogist

Self Cite

View full text Add to dashboard Cite

Seidite-(Ce), Na 4 (Ce,Sr) 2 {Ti(OH) 2 (Si 8 O 18 )}(O,OH,F) 4 •5H 2 O, is a titanosilicate recently discovered in the Yubileynaya pegmatite at Mount Karnasurt, Lovozero alkaline massif, Kola Peninsula, Russia. Grains consist of disordered [010] fibers; no single crystals suitable for X-ray diffraction have found. On the basis of chemical composition, electron and X-ray powderdiffraction data, and by comparison with the structure of miserite, KCa 5 (Si 2 O 7 )(Si 6 O 15 )(OH)F, a structure model for seidite-(Ce) has been developed in space group C2/c [a 24.61(5), b 7.23(1), c 14.53(3) Å, ␤ 94.6(3)°, Z = 4]. In the crystal structure of seidite-(Ce), the isolated eight-membered silicate channels of miserite are condensed into (100) layers that are connected by isolated TiO 6 octahedra to form a framework. In the chemical formula, the composition of the framework is shown within braces. There are two types of channels involving TiO 6 octahedra and SiO 4 tetrahedra: one is eight-membered and is parallel to the silicate channel along [010]; the other is ten-membered and extends along [001]. Cations other than Si and Ti occur within the channels, together with H 2 O groups and OH,F anions. The Na cations are easily exchanged for Tl, K, Rb, Cs and Ba, indicating the microporous behavior of the seidite-(Ce) structure. We describe the mero-plesiotype modular aspects of seidite-(Ce) and related compounds belonging to the rhodesite group. SOMMAIRELa seidite-(Ce), Na 4 (Ce,Sr) 2 {Ti(OH) 2 (Si 8 O 18 )}(O,OH,F) 4 •5H 2 O, est un titanosilicate découvert récemment dans la pegmatite de Yubileynaya, au mont Karnasurt, complexe alcalin de Lovozero, péninsule de Kola, en Russie. Les grains sont des fibres [010] désordonnées; aucun monocristal apte à une étude par diffraction X n'a été trouvé. A la lumière de données sur la composition chimique, la diffraction d'électrons et la diffraction X (méthode des poudres), et par comparaison avec la structure de la misérite, KCa 5 (Si 2 O 7 )(Si 6 O 15 )(OH)F, nous avons développé un modèle structural pour la seidite-(Ce) dans le groupe spatial C2/c [a 24.61(5), b 7.23(1), c 14.53(3) Å, ␤ 94.6(3)°, Z = 4]. Dans cette structure, les canaux isolés à huit membres dans la trame silicatée de la misérite sont condensés en couches (100) connectées par des octaèdres TiO 6 isolés pour former une trame. Dans la formule chimique, la composition de la trame paraît entre crochets. La structure contient deux sortes de canaux impliquant des octaèdres TiO 6 et des tétraèdres SiO 4 : un de ceux-ci possède huit membres, et il est parallèle au canal dans la trame silicatée, le long de [010]; l'autre en possède dix, et il est disposé le long de [001]. Les cations autres que Si et Ti sont situés dans les canaux, ainsi que les groupes H 2 O et les anions OH,F. Les cations Na sont facilement échangeables pour Tl, K, Rb, Cs et Ba, indication d'un § E-mail address: giovanni.ferraris@unito.it 1184 THE CANADIAN MINERALOGISTcomportement microporeux par la structure de la seidite-(Ce). Nous décrivons les aspects modul...

show abstract

“…It was difficult to find crys tals suitable for crystal structure work, and Ferraris et al (2001a) proposed a model for the crystal struc ture of bornemanite using selected area electron dif fraction (SAED) data, X ray powder diffraction data and a polysomatic model building approach. Ferraris et al (2001a) reported sp. gr.…”

Section: Bornemanitementioning

confidence: 99%

Predictive crystal-chemical relations in Ti-silicates based on the TS block

Sokolova

2010

Geol. Ore Deposits

View full text Add to dashboard Cite

In a group of minerals of reasonable complexity in which the structure topology is related but not identical, the general relation between structure topology and chemical composition is not known. This prob lem is of major significance. The structural hierarchy and stereochemistry are described for 27 titanium dis ilicate minerals that contain the TS (titanium silicate) block, a central trioctahedral (O) sheet and two adja cent (H) sheets of [5] and [6] coordinated polyhedra and (Si 2 O 7 ) groups and related delindeite. The TS block is characterized by a planar cell based on translation vectors, t 1 and t 2 , with t 1 ~ 5.5 and t 2 ~ 7 Å and t 1 ∧ t 2 close to 90°. The general formula of the TS block is (Si 2 O 7 ) 2 X 4 + n , where and = cations of the H and O sheets; M H = Ti (= Ti + Nb), Zr, Mn 2+ , Ca; M O = Ti, Zr, Mn 2+ , Ca, Na; A P and B P are cations at the peripheral (P) sites = Na, Ca, Ba; X = anions = O, OH, F; n = 0, 2, 4; the core part of the TS block is shown in bold and is invariant. Cations in each sheet of the TS block form a close packed layer and the three layers are cubic close packed. There are three topologically distinct TS blocks, depending on the type of linkage of two H sheets and the central O sheet. The H sheets of one TS block attach to the O sheet in the same manner. All structures consist of a TS block and an I (intermediate) block that comprises atoms between two TS blocks. Usually, the I block consists of alkali and alkaline earth cations, (H 2 O) groups and oxyanions (PO 4 ) 3-, (SO 4 ) 2-and (CO 3 ) 2-. These structures naturally fall into four groups, based on differences in topology and stereochemistry of the TS block. In Group I, Ti = 1 apfu Ti occurs in the O sheet, and (Si 2 O 7 ) groups link to a Na polyhedron of the O sheet (linkage 1). In Group II, Ti = 2 apfu, Ti occurs in the H sheet, and (Si 2 O 7 ) groups link to two M 2+ octahedra of the O sheet adjacent along t 2 (linkage 2). In Group III, Ti = 3 apfu, Ti occurs in the O and H sheets, and (Si 2 O 7 ) groups link to the Ti octahedron of the O sheet (linkage 1). In Group IV, Ti = 4 apfu (the maximum possible content of Ti in the TS block), Ti occurs in the O and H sheets, and (Si 2 O 7 ) groups link to two Ti octahedra of the O sheet adjacent along t 1 (linkage 3). The stability of the TS block is due to the ability of Ti (Nb) to have an extremely wide range in Ti (Nb) anion bond lengths, 1.68-2.30 Å, which allows the chemical composition of the TS block to vary widely. In crystal structures so far known, only one type of TS block occurs in a structure. The TS block propagates close packing of cations onto the I block. The gen eral structural principles and the relation between structure topology and chemical composition are described for the TS block minerals. These principles allow prediction of structural arrangements and possible chemi cal compositions, and testing whether or not all aspects of the structure and chemical formula of a mineral are correct. Here, I show how these principles work, and review recent...

show abstract

A Structural Model of the Layer Titanosilicate Bornemanite Based on Seidozerite and Lomonosovite Modules

Cited by 16 publications

References 12 publications

From structure topology to chemical composition. VI. Titanium silicates: the crystal structure and crystal chemistry of bornemanite, a group III Ti-disilicate mineral

From structure topology to chemical composition. VI. Titanium silicates: the crystal structure and crystal chemistry of bornemanite, a group III Ti-disilicate mineral

THE CRYSTAL STRUCTURE OF SEIDITE-(Ce), Na4(Ce,Sr)2 (O,OH,F)4{middle dot}5H2O, A MODULAR MICROPOROUS TITANOSILICATE OF THE RHODESITE GROUP

Predictive crystal-chemical relations in Ti-silicates based on the TS block

Contact Info

Product

Resources

About