|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
University of Western Ontario, Department of Earth Sciences, London, ON, Canada
University of Saskatchewan, Canada
Crystals of binary (LREE+HREE)-bearing fluorapatite [La,Gd-FAp, Ce,Dy-FAp, Pr,Er-FAp, Eu,Lu-FAp: Ca (sub 10-x-2y) Na y REE (sub x-y) (P (sub 1-x) Si x O 4 ) 6 A 2 , with x = 0.12-0.20, y = 0.26-0.42; P6 3 /m] have been grown from H 2 O-rich phosphate-fluoride melts, and their structures refined at room temperature with single-crystal X-ray intensities to R = 0.017-0.022. These binary-REE-substituted fluorapatite samples have REE site-occupancy ratios (REE-Ca2/REE-Cal) of 2.32, and 2.32, 2.03, 1.71, respectively, which are 0.47-0.16 smaller than corresponding ratios calculated using data for reference single-REE-substituted fluorapatite. Discrepancies in intracrystalline partitioning between multiple-REE-substituted apatites and single-REE-substituted fluorapatite decrease with a decrease in REE concentration, becoming negligible at 0.2-0.3 total REE cations pfu in synthetic binary-REE-substituted fluorapatite and at trace abundances of REE in natural apatites. However, quantitative transference of laboratory REE site preferences to natural apatites is frustrated by the compositional complexity in nature. In the synthetic fluorapatite, there is a profound change in the spatial accommodation of REE in the apatite structure at about the position of Nd in the 4f transition-metal series, corresponding to the peak in the experimental uptake curve. Discrepancies in intracrystalline partitioning between binary-REE- and single-REE-substituted fluorapatite are attributed to non-ideal mixing of LREE and HREE that results in contraction of the Ca1 coordination sphere.
This record provided courtesy of AGI/GeoRef.
This article has been cited by other articles:
|
|
 |
|
  H. E. Mason, F. M. McCubbin, A. Smirnov, and B. L. Phillips Solid-state NMR and IR spectroscopic investigation of the role of structural water and F in carbonate-rich fluorapatite American Mineralogist, April 1, 2009; 94(4): 507 - 516. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Luo, J. M. Hughes, J. Rakovan, and Y. Pan Site preference of U and Th in Cl, F, and Sr apatites American Mineralogist, February 1, 2009; 94(2-3): 345 - 351. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Povondra, R. Skala, and R. Chapman HYDROTHERMAL ASSEMBLAGE OF Cl-, F- AND OH-BEARING APATITE-GROUP MINERALS FROM MAGLOVEC, NEAR PRESOV, SLOVAKIA Can Mineral, December 1, 2007; 45(6): 1355 - 1366. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. S. Henderson and Y. Pan S3: SULFIDES, STRUCTURES AND SYNCHROTRON LIGHT A TRIBUTE TO MICHAEL E. FLEET: PREFACE Can Mineral, October 1, 2005; 43(5): 1449 - 1456. [Full Text] [PDF]
|
|
|
|
|
|
M. E. Fleet, M. E. Fleet, X. Liu, and P. L. King Accommodation of the carbonate ion in apatite: An FTIR and X-ray structure study of crystals synthesized at 2-4 GPa American Mineralogist, October 1, 2004; 89(10): 1422 - 1432. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Harlov, D. E. Harlov, and H.-J. Forster Fluid-induced nucleation of (Y+REE)-phosphate minerals within apatite: Nature and experiment. Part II. Fluorapatite American Mineralogist, August 1, 2003; 88(8-9): 1209 - 1229. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Pan, M. E. Fleet, N. Chen, J. A. Weil, and M. J. Nilges SITE PREFERENCE OF Gd IN SYNTHETIC FLUORAPATITE BY SINGLE-CRYSTAL W-BAND EPR AND X-RAY REFINEMENT OF THE STRUCTURE: A COMPARATIVE STUDY Can Mineral, August 1, 2002; 40(4): 1103 - 1112. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Harlov, H.-J. Forster, and T. G. Nijland Fluid-induced nucleation of (Y + REE)-phosphate minerals within apatite: Nature and experiment. Part I. Chlorapatite American Mineralogist, February 1, 2002; 87(2-3): 245 - 261. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Pan and M. E. Fleet Compositions of the Apatite-Group Minerals: Substitution Mechanisms and Controlling Factors Reviews in Mineralogy and Geochemistry, January 1, 2002; 48(1): 13 - 49. [Full Text] [PDF]
|
|
|
|
|
|
G. A. Waychunas Apatite Luminescence Reviews in Mineralogy and Geochemistry, January 1, 2002; 48(1): 701 - 742. [Full Text] [PDF]
|
|
|
|
|
|
N. Chen, Y. Pan, and J. A. Weil Electron paramagnetic resonance spectroscopic study of synthetic fluorapatite: Part I. Local structural environment and substitution mechanism of Gd3+ at the Ca2 site American Mineralogist, January 1, 2002; 87(1): 37 - 46. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Oberti, L. Ottolini, G. D. Ventura, and G. C. Parodi On the symmetry and crystal chemistry of britholite: New structural and microanalytical data American Mineralogist, September 1, 2001; 86(9): 1066 - 1075. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Fleet, X. Liu, and Y. Pan Rare-earth elements in chlorapatite [Ca10(PO4)6Cl2]: Uptake, site preference, and degradation of monoclinic structure American Mineralogist, October 1, 2000; 85(10): 1437 - 1446. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Rakovan and J. M. Hughes STRONTIUM IN THE APATITE STRUCTURE: STRONTIAN FLUORAPATITE AND BELOVITE-(Ce) Can Mineral, August 1, 2000; 38(4): 839 - 845. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
