Coulsellite, CaNa3AlMg3F14, a rhombohedral pyrochlore with 1:3 ordering in both A and B sites, from the Cleveland Mine, Tasmania, Australia

被引：11

作者：

Mumme, W. Gus ^{[1
]}

Grey, Ian E. ^{[1
]}

Birch, William D. ^{[2
]}

Pring, Allan ^{[3
]}

Bougerol, Catherine ^{[4
]}

Wilson, Nicholas C. ^{[1
]}

机构：

[1] CSIRO Minerals, Clayton, Vic 3169, Australia

[2] Victoria & Albert Museum, Geosci Sect, Melbourne, Vic 3001, Australia

[3] S Australian Museum, Dept Mineral, Adelaide, SA 5000, Australia

[4] Equipe CEA CNRS NPSC SP2M DRFMC CEA, F-38054 Grenoble, France

来源：

AMERICAN MINERALOGIST | 2010年 / 95卷 / 5-6期

关键词：

Rhombohedral pyrochlore; new fluoride mineral; structure determination; 1:3 cation ordering in CaNa3AlMg3F14; RALSTONITE;

D O I：

10.2138/am.2010.3360

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

Coulsellite, CaNa3AlMg3F14, from the Cleveland tin mine at Luina, western Tasmania, has a rhombohedral distortion of the cubic pyrochlore A(2)B(2)X(6)Y structure, with a = 7.1756(1) angstrom, alpha = 59.867(1)degrees, space group R (3) over barm, Z = 1. The corresponding hexagonal cell parameters are a = 7.1620(1) angstrom, c = 17.5972(3) angstrom. The crystals are multiply twinned about threefold axes of the pseudocubic cell. The structure was determined using X-ray data collected on a twinned crystal and refined to R-obs = 0.027 for 452 observed reflections with I > 2 sigma(I) The structure is possibly unique among published structures of pyrochlore-like minerals in having full 1:3 ordering of Ca:Na in the A sites and Al:Mg in the B sites. Transmission electron photomicrographs show a nanodomain structure due to twinning on a scale of similar to 5 nm.

引用

页码：736 / 740

页数：5

共 18 条

[1]

[Anonymous], 1997, SHELX 97 PROGRAM CRY

[2] A CALCIAN RALSTONITE-LIKE MINERAL FROM THE CLEVELAND MINE, TASMANIA, AUSTRALIA [J].

BIRCH, WD ;

PRING, A .

MINERALOGICAL MAGAZINE, 1990, 54 :599-602

[3]

BLOUNT AM, 1974, AM MINERAL, V59, P41

[4] The crystal structure of ingersonite, Ca3Mn2+Sb5+4O14, and its relationships with pyrochlore [J].

Bonazzi, Paola ;

Bindi, Luca .

AMERICAN MINERALOGIST, 2007, 92 (5-6) :947-953

[5] BOND-VALENCE PARAMETERS FOR SOLIDS [J].

BRESE, NE ;

OKEEFFE, M .

ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 1991, 47 :192-197

[6]

EFFENBERGER VH, 1984, NEUES JB MINERALOGIE, P97

[7]

ERCIT TS, 1986, CAN MINERAL, V24, P655

[8]

Farrugia L. J., 1999, Journal of Applied Crystallography, V32, P837, DOI [DOI 10.1107/S0021889812029111, 10.1107/S0021889899006020, DOI 10.1107/S0021889899006020]

[9] The structure of multiple twinned CsMgInF6 and its relationship to other pyrochlore derived fluorides [J].

Friese, K ;

Gesland, JY ;

Grzechnik, A .

ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 2005, 220 (07) :614-621

[10]

GOREAUD M, 1980, AM MINERAL, V65, P953

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