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Title: Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects

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.

Authors:
 [1];  [2];  [3];  [2]
  1. Moscow State University (Russian Federation), E-mail: yakubol@geol.msu.ru
  2. Philipps-Universitaet Marburg (Germany)
  3. Moscow State University (Russian Federation)
Publication Date:
OSTI Identifier:
21091392
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)
Country of Publication:
United States
Language:
English
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

Citation Formats

Yakubovich, O. V., Massa, W., Pekov, I. V., and Gavrilenko, P. G. Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects. United States: N. p., 2007. Web. doi:10.1134/S1063774507010087.
Yakubovich, O. V., Massa, W., Pekov, I. V., & Gavrilenko, P. G. Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects. United States. doi:10.1134/S1063774507010087.
Yakubovich, O. V., Massa, W., Pekov, I. V., and Gavrilenko, P. G. Thu . "Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects". United States. doi:10.1134/S1063774507010087.
@article{osti_21091392,
title = {Crystal structure of tveitite-(Y): Fractionation of rare-earth elements between positions and the variety of defects},
author = {Yakubovich, O. V. and Massa, W. and Pekov, I. V. and Gavrilenko, P. G.},
abstractNote = {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.},
doi = {10.1134/S1063774507010087},
journal = {Crystallography Reports},
number = 1,
volume = 52,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
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