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 Google Scholar Google Scholar Articles by Sokolova, E. Articles by Pautov, L. A. Search for Related Content GeoRef GeoRef Citation

TURANITE, Cu²⁺ ₅ (V⁵⁺O₄)₂ (OH)₄, FROM THE TYUYA–MUYUN RADIUM–URANIUM DEPOSIT, OSH DISTRICT, KYRGYZSTAN: A NEW STRUCTURE FOR AN OLD MINERAL

Elena Sokolova^1,, Frank C. Hawthorne¹, Vladimir V. Karpenko², Atali A. Agakhanov² and Leonid A. Pautov^2,¶

¹ Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
² Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii Pr. 18/2, RU–117071 Moscow, Russia

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

The crystal structure of turanite, Cu₅ ²⁺ (V⁵⁺O₄)₂ (OH)₄, from the Tyuya–Muyun Ra–U deposit, the Alai Ridge foothills, Osh district, Kyrgyzstan, triclinic, space group P, a 5.3834(2), b 6.2736(3), c 6.8454(3) Å, 86.169(1), ß 91.681(1), 92.425(1)°, V 230.38(2) ų, Z = 1, has been solved by direct methods and refined to an R index of 2.2% based on 1332 observed [F_o > 4F] unique reflections measured with MoK X-radiation and a Bruker P4 diffractometer equipped with a CCD detector. Chemical analysis by electron microprobe gave CuO 62.94, V₂O₅ 28.90, H₂O 5.85, sum 97.69 wt.%; the amount of H₂O was determined by crystal-structure analysis. The resulting empirical formula on the basis of 12 anions (including OH = 4 apfu) is Cu_4.97 ²⁺ (V⁵⁺O₄)₂ (OH)_4.08. There are three distinct Cu sites fully occupied by Cu²⁺ and octahedrally coordinated by four O atoms and two (OH) groups, with <Cu–O,OH> = 2.115 Å. The (Cu₆) octahedra ( = O, OH) form a sheet of edge-sharing octahedra (with vacancies, oct : vac = 5 : 1) parallel to (011). On each side of the vacant octahedron, a (VO₄) tetrahedron is attached to three anions of the sheet and points away from the sheet to be attached to an anion of the adjacent sheet. Thus the (Cu₆) octahedra and (VO₄) tetrahedra constitute a framework, within which the sheets are also linked by hydrogen bonding from (OH) groups of one sheet to O anions of adjacent sheets. Turanite can be considered as a framework structure with interrupted sheets of (Cu₆) octahedral decorated by (VO₄) tetrahedra, and is related to the structures of cornubite, cianciulliite, gordaite, bechererite, chalcophyllite, ramsbeckite and simonkolleite.

Keywords: turanite, crystal structure, Tyuya–Muyun, Osh district, Kyrgyzstan.