Bibliographic Citation
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| DOI | 10.1134/S1063774507010087 |
| Title | Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects |
| Creator/Author | Yakubovich, O. V. [Moscow State University (Russian Federation)], E-mail: yakubol@geol.msu.ru ; Massa, W. [Philipps-Universitaet Marburg (Germany)] ; Pekov, I. V. [Moscow State University (Russian Federation)] ; Gavrilenko, P. G. [Philipps-Universitaet Marburg (Germany)] |
| Publication Date | 2007 Feb 15 |
| OSTI Identifier | OSTI ID: 21091392 |
| Other Number(s) | Journal ID: ISSN 1063-7745; CYSTE3; TRN: US07L1575101602 |
| Resource Type | Journal Article |
| Resource Relation | Journal Name: Crystallography Reports; Journal Volume: 52; Journal Issue: 1; Other Information: DOI: 10.1134/S1063774507010087; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA) |
| Subject | 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANIONS; CALCIUM COMPOUNDS; CATIONS; CRYSTAL DEFECTS; CRYSTALS; FLUORIDES; GRAPHITE; PEGMATITES; RARE EARTH COMPOUNDS; SODIUM COMPOUNDS; SPACE GROUPS; TRIGONAL LATTICES; X-RAY DIFFRACTION; YTTRIUM COMPOUNDS |
| Description/Abstract | The crystal structure of the mineral tveitite-(Y) (Y{sub 0.883}Na{sub 0.106}) (Ca{sub 0.841}LREE{sub 0.159})(Ca{sub 0.716}Na{sub 0.204}HREE{sub 0.080})(Ca{sub 0.0=} 9{sub 2}Na{sub 0.074})F{sub 6.952} from amazonite pegmatites of Rov-Gora Mountain (Keivy, Kola Peninsula) is determined using X-ray diffraction (Stoe IPDS diffractometer, {lambda}MoK{sub {alpha}}, graphite monochromator, 2{theta}{sub max} = 63.5{sup o}, R = 0.051 for 1542 reflections). The main crystal data are as follows: a = 17.020(2) A, c = 9.679(2) A, V = 2428.2(4) A{sup 3}, space group R3-bar, Z = 18, and {rho}{sub calcd} = 4.00 g/cm{sup 3}. The idealized structural formula of the mineral is represented as (Y,Na){sub 6}(Ca,LREE){sub 6}(Ca,Na,HREE){sub 6}(Ca,Na)F{sub 42} (Z = 3). The defect structure of the mineral manifests itself in a mixed occupation of all four independent cation positions and in a randomly disordered distribution of fluorine atoms over the majority of anion positions. It is shown that the crystal structure of tveitite-(Y) fulfills the function of an 'Eratosthenes sieve' for yttrium cations and two groups of lanthanide cations, so that these cations are distributed over three different positions. |
| Country of Publication | United States |
| Language | English |
| Format | Medium: X; Size: page(s) 71-79 |
| System Entry Date | 2009 Dec 17 |
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