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RESEARCH PRODUCT

Towards a revisitation of vesuvianite-group nomenclature: the crystal structure of Ti-rich vesuvianite from Alchuri, Shigar Valley

Dmitry I. BelakovskiyNikita V. ChukanovFarit G. VagizovRamil R. GainovRamil R. GainovRamil R. GainovVyacheslav S. RusakovRamiza K. RastsvetaevaSergey M. AksenovSergey M. AksenovTaras L. PanikorovskiiKonstantin A. Lyssenko

subject

Chromatography GasMagnetic Resonance SpectroscopySpectrophotometry InfraredCrystal chemistryIronInfrared spectroscopyMineralogyElectron microprobeCrystal structureengineering.materialCrystallography X-Ray010502 geochemistry & geophysics01 natural sciencesSpectroscopy MossbauerTetragonal crystal systemX-Ray Diffraction0502 economics and businessMössbauer spectroscopyMaterials ChemistryPakistanVesuvianite0105 earth and related environmental sciencesTitaniumMineralsChemistry05 social sciencesMetals and AlloysAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsCrystallographyengineering050211 marketingPowdersPowder diffraction

description

Vesuvianite containing 5.85 wt% TiO2from an Alpine-cleft-type assemblage outcropped near Alchuri, Shigar Valley, Northern Areas, has been investigated by means of electron microprobe analyses, gas-chromatographic analysis of H2O, X-ray powder diffraction, single-crystal X-ray structure refinement,27Al NMR,57Fe Mössbauer spectroscopy, IR spectroscopy and optical measurements. Tetragonal unit-cell parameters are:a= 15.5326 (2),c= 11.8040 (2) Å, space groupP4/nnc. The structure was refined to finalR1= 0.031,wR2= 0.057 for 11247I> 2σ(I). A general crystal-chemical formula of studied sample can be written as follows (Z= 2):[8–9](Ca17.1Na0.9)[8]Ca1.0[5](Fe2+0.44Fe3+0.34Mg0.22)[6](Al3.59Mg0.41)[6](Al4.03Ti2.20Fe3+1.37Fe2+0.40) (Si18O68) [(OH)5.84O2.83F1.33]. The octahedral siteY2 is Al-dominant and does not contain transition elements. Another octahedral siteY3 is also Al-dominant and contains Fe2+, Fe3+and Ti. The siteY1 is split intoY1aandY1bpredominantly occupied by Fe2+and Fe3+, respectively. The role of theY1 site in the diversity of vesuvianite-group minerals is discussed.

yearjournalcountryeditionlanguage
2016-09-29Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials
https://doi.org/10.1107/s2052520616010246