Crystallochemical Structure of Tourmalines Inferred from Mössbauer Spectroscopy |
| J. Kraczkaa and A. Pieczkab aH. Niewodniczañski Institute of Nuclear Physics, Radzikowskiego 152, 31-342 Cracow, Poland bUniversity of Mining and Metallurgy, Mickiewicza 30, 30-059 Cracow, Poland |
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| In the Y octahedra of tourmalines theoretically may occur ions of Fe2+ and Fe3+. The authors discuss Mössbauer measurements and confirm the ordered model of ionic distribution at these sites: the presence of Fe3+ ions in the Y octahedra and Al3+ ions in the Z octahedra. The spectra of different tourmalines annealed at temperatures ranging from 873 K to 1153 K show that Fe3+ ions can occur in both of these sites. The annealing has changed the symmetry of the neighbourhood of iron ions at the octahedral sites. It has been shown that the doublets with QS<2.00 mm/s should not been attributed to Fe2+(Z). Also new results corroborating the existence of the iron ions in the mixed valence state in tourmalines have been presented. |
| DOI: 10.12693/APhysPolA.100.743 PACS numbers: 76.80.+y |