Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Résumé Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sokolova, E. Articles by Hawthorne, F. C. Search for Related Content GeoRef GeoRef Citation

THE CRYSTAL CHEMISTRY OF SILICATE MINERALS WITH CHAINS OF (TiO₆) OCTAHEDRA

Elena Sokolova and Frank C. Hawthorne

Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada

E-mail address: elena_sokolova{at}umanitoba.ca

Chains of (TiO₆) octahedra occur in several crystal structures as fundamental building blocks, confirming the tendency of self-polymerization for (TiO₆) octahedra. There are two topologically distinct types of chains based on linkage of (TiO₆) octahedra, corner-sharing chains and edge-sharing chains. In this paper, we focus on the diversity of linkages between chains of (TiO₆) octahedra and (SiO₄) tetrahedra. In Ti-silicate structures based on chains of corner-sharing (Ti⁴⁺₆) octahedra, the chains are neither branched nor looped; they are topologically simple [Ti₅] chains. The chemical formulae of such structures may be written in a very general way as Na_2a (TiO)_a [Si_c O_2(a+c)] (H₂O)_n and Na_a (Ti{OH})_a [Si_c O_2(a+c)] (H₂O)_n, where a and c are integers. These are not arbitrary formulae; the bond topology is such that all anions obey the valence-matching principle. The formulae of batisite, narsarsukite, titanite, the minerals of the labuntsovite group and quartz (Ti-free) are in accord with this general formula. In structures based on chains of edge-sharing (Ti⁴⁺₆) octahedra, the chains may be simple, branched or looped, and there is usually another complicating factor to the bond topology: additional components [e.g., (PO₄), Cl, ^[4]Al, Cr³⁺] are common. None of the resultant structures have cubic, hexagonal or trigonal symmetry. There are numerous silicate minerals containing chains of (TiO₆) octahedra. In contrast, layers of (TiO₆) octahedra are rare and occur only in four structure types, and frameworks of (TiO₆) octahedra are not known in silicate minerals.

Keywords: titanium silicates, (TiO₆) octahedron, chain, layer.

This article has been cited by other articles:

				U. Kolitsch, M. Wierzbicka-Wieczorek, and E. Tillmanns CRYSTAL CHEMISTRY AND TOPOLOGY OF TWO FLUX-GROWN YTTRIUM SILICATES, BaKYSi2O7 AND Cs3YSi8O19 Can Mineral, April 1, 2009; 47(2): 421 - 431. [Abstract] [Full Text] [PDF]

				E. Sokolova, F. C. Hawthorne, and A. P. Khomyakov POLYPHITE AND SOBOLEVITE: REVISION OF THEIR CRYSTAL STRUCTURES Can Mineral, October 1, 2005; 43(5): 1527 - 1544. [Abstract] [Full Text] [PDF]

				E. Sokolova, F. C. Hawthorne, G. Della Ventura, and P. M. Kartashov CHEVKINITE-(Ce): CRYSTAL STRUCTURE AND THE EFFECT OF MODERATE RADIATION-INDUCED DAMAGE ON SITE-OCCUPANCY REFINEMENT Can Mineral, August 1, 2004; 42(4): 1013 - 1025. [Abstract] [Full Text] [PDF]