Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by GRAMACCIOLI, C. M. Articles by DEMARTIN, F. Search for Related Content GeoRef GeoRef Citation

The formation of scandium minerals as an example of the role of complexes in the geochemistry of rare earths and HFS elements

¹ Dipartimento di Scienze della Terra, Universitá di Milano, Via Botticelli 23, 20133 Milano, Italy
² CNR, Centro studio per la geodinamica alpina e quaternaria, Via Botticelli 23, 20133 Milano, Italy
³ Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universitá di Milano, Via Venezian 21, 20133 Milano, Italy

e-mail: carlo{at}r10.terra.unimi.it

The stability constants of the fluoride complexes of scandium are much higher than those of most other elements; in particular, with respect to the REE, these complexes are in general much more stable than it would be expected on the basis of the corresponding ionic radii only. Accordingly, the presence of fluorides should easily lead to differentiation between scandium and other elements, including the REE, at times giving origin to specific minerals; a similar behaviour can be expected for zirconium or other HFS elements, whose complexes with the fluoride ion are also very stable, and in general for other ligands, such as for instance the phosphate and carbonate ions. Therefore, rather than the specific properties of sites in crystal structures, the formation of complexes of different stability in the depositing solutions and their disruption may become instead fundamental in explaining the enrichment of these elements, and the consequent formation of particular minerals of unusual composition. The practical consequences of this possibility are supported by crystal-chemical considerations and by a number of examples observed in Alpine veins and in pegmatites.

Key-words: rare earths, HFS elements, scandium, yttrium, fluoride complexes, phosphate complexes, geochemistry.

This article has been cited by other articles:

				F. Pezzotta, V. Diella, and A. Guastoni Scandium silicates from the Baveno and Cuasso al Monte NYF-granites, Southern Alps (Italy): Mineralogy and genetic inferences American Mineralogist, August 1, 2005; 90(8-9): 1442 - 1452. [Abstract] [Full Text] [PDF]

				C. M. GRAMACCIOLI, I. CAMPOSTRINI, and P. ORLANDI Scandium minerals in the miaroles of granite at Baveno, Italy European Journal of Mineralogy, December 1, 2004; 16(6): 951 - 956. [Abstract] [Full Text] [PDF]

				C. Spandler, J. Hermann, and D. Rubatto Exsolution of thortveitite, yttrialite, and xenotime during low-temperature recrystallization of zircon from New Caledonia, and their significance for trace element incorporation in zircon American Mineralogist, November 1, 2004; 89(11-12): 1795 - 1806. [Abstract] [Full Text] [PDF]

				Y. Moelo, Y. Lulzac, O. Rouer, P. Palvadeau, E. Gloaguen, and P. Leone SCANDIUM MINERALOGY: PRETULITE WITH SCANDIAN ZIRCON AND XENOTIME-(Y) WITHIN AN APATITE-RICH OOLITIC IRONSTONE FROM SAINT-AUBIN-DES-CHATEAUX, ARMORICAN MASSIF, FRANCE Can Mineral, December 1, 2002; 40(6): 1657 - 1673. [Abstract] [Full Text] [PDF]

				C. M. Gramaccioli, V. Diella, F. Demartin, P. Orlandi, and I. Campostrini CESIAN BAZZITE AND THORTVEITITE FROM CUASSO AL MONTE, VARESE, ITALY: A COMPARISON WITH THE MATERIAL FROM BAVENO, AND INFERRED ORIGIN Can Mineral, December 1, 2000; 38(6): 1409 - 1418. [Abstract] [Full Text] [PDF]