ISSN:
1432-2021
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract Tourmaline solid solutions containing Fe, Fe+ Ti, Cr, Ni, Cu, Co, Mn chromophoric centers have been grown hydrothermally at 650° C and 1,5 kbar on natural seeding plates close to the elbaite composition. The newly grown tourmalines were characterized by chemical analyses and optical absorption spectroscopy in the range 26316-5000 cm-1 at 297 K and in the range 26316-9090 cm-1 at 77 K. Most characteristic of Fe2+, Fe3+-bearing specimens is the presence of intensive σpolarized absorption bands caused by exchange-coupled Fe2+-Fe3+ pairs in Y- and Z-sites of the tourmaline structure. An additional intensive absorption band 12500 cm-1 (σ-polarisation) appears in some specimens but is not yet found in spectra of natural tourmalines. The colour and spectroscopic properties of the Fe3+, Mn3+ and Cu2+ containing tourmalines are significantly affected by the presence of even the smallest Li-contents. The results suggest that Fe2+, Cu2+, Co2+, Ni2+-ions occupy, predominantly, Y-sites of the tourmaline structure, whereas the Cr3+-ions seem to enter the smaller Z-octachedra.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00200123
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