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http://hdl.handle.net/1843/83720| Type: | Artigo de Periódico |
| Title: | On the greenish-yellow color of natural Brazilian titanite |
| Authors: | Eder Luiz Tolentino Junior Coralie Heinis Dias Mario Luiz de Sá Carneiro Chaves Klaus Wilhelm Heinrich Krambrock Mauricio Veloso Brant Pinheiro |
| Abstract: | Natural greenish-yellow titanites from two localities in Brazil (Bananal/Capelinha, MG and Xambioá, TO) were characterized by electron paramagnetic resonance (EPR) and optical absorption. Along with vanadyl ions (VO2+) substituting Ti4+, two other paramagnetic centers were identified: the Fe3+ and the Mn2+. For the VO2+, the principal values and orientations of the g and A tensors were derived from a careful analysis of the angular dependence of the EPR spectra. The obtained results, although different to previously reported data, still support the model for the VO2+ bonds to the nearest oxygen (O1) in the TiO6-distorted octahedra. In addition, the titanite optical absorption spectra were analyzed, and the yellow color was ascribed to Fe3+ ↔ O2− ligand–metal charge transfer transitions (LMCT) in the near-ultraviolet, extending to the violet and blue spectral ranges. The VO2+ center seen by EPR was in low concentration and had no visible effect on the color. Finally, γ-irradiation up to 200 kGy and thermal treatments in oxidizing/reducing atmospheres up to 600–700 °C also had no big influence on the dominant yellow color. |
| Subject: | Ressonância paramagnética eletrônica Ferro |
| language: | eng |
| metadata.dc.publisher.country: | Brasil |
| Publisher: | Universidade Federal de Minas Gerais |
| Publisher Initials: | UFMG |
| metadata.dc.publisher.department: | ICX - DEPARTAMENTO DE FÍSICA |
| Rights: | Acesso Restrito |
| metadata.dc.identifier.doi: | https://doi.org/10.1007/s00269-018-0998-2 |
| URI: | http://hdl.handle.net/1843/83720 |
| Issue Date: | 2019 |
| metadata.dc.url.externa: | https://link.springer.com/article/10.1007/s00269-018-0998-2 |
| metadata.dc.relation.ispartof: | Physics and Chemistry of Minerals |
| Appears in Collections: | Artigo de Periódico |
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