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Crystal structure and Raman spectrum of hydroxyl-bästnasite-(Ce), CeCO3(OH).
- Source :
-
American Mineralogist . Apr2008, Vol. 93 Issue 4, p698-698. 1p. - Publication Year :
- 2008
-
Abstract
- Hydroxyl-bästnasite-(Ce), ideally CeCO3(OH), had been regarded isostructural with bästnasite-(Ce), CeCO3F, the dominant member of the bästnasite family that produces ~70% of the world's supply of rare-earth elements. Using single-crystal X-ray diffraction and Raman spectroscopy, our structural analysis on hydroxyl-bästnasite-(Ce) shows that the previous assumption is incorrect. The crystal structure of hydroxyl-bästnasite-(Ce) possesses P6̄ symmetry with unit-cell parameters a = 12.4112(2), c = 9.8511(3) Å, and V = 1314.2(1) ų, in contrast to the space group P6̄2c and a ≈ 7.10, c ≈ 9.76 Å, and V ≈ 430 ų for bästnasite-(Ce). Moreover, there are 6, 3, and 5 symmetrically-distinct CO3 groups, Ce cations, and (OH/F) ions, respectively, in hydroxyl-bästnasite-(Ce), but 1, 1, and 2 in bästnasite-(Ce). The two structures, nevertheless, are similarly characterized by the layers of CO3 groups alternating with the Ce-(OH/F) layers along the c direction. The Raman spectrum of hydroxyl-bästnasite-(Ce) is dominated by three strong bands at 1080, 1087, and 1098 cm-1 in the CO3 symmetrical stretching region, along with at least four bands in the OH stretching region. Our study further suggests that natural hydroxyl-bästnasite-(Nd) is most likely isotypic with hydroxyl-bästnasite-(Ce), rather than with bästnasite-(Ce), as previously proposed. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0003004X
- Volume :
- 93
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- American Mineralogist
- Publication Type :
- Academic Journal
- Accession number :
- 31770083
- Full Text :
- https://doi.org/10.2138/am.2008.2827