The role of different network modifying cations on the speciation of the Co2+ complex in silicates and implication in the investigation of historical glasses
| Autor: | Andrea Ceglia, Susanna Bracci, Márcia Vilarigues, Cristina Fornacelli |
|---|---|
| Přispěvatelé: | Multidisciplinary Archaeological Research Institute, Brussels Photonics Team, Applied Physics and Photonics |
| Rok vydání: | 2018 |
| Předmět: |
coordination
Optical fiber Analytical chemistry chemistry.chemical_element 02 engineering and technology Cobalt(Ii) 01 natural sciences Analytical Chemistry law.invention Ion Glass structure Absorbance law Instrumentation Spectroscopy FORS 010401 analytical chemistry Near-infrared spectroscopy ALKALI-BORATE GLASSES TRANSITION-METAL IONS OPTICAL-ABSORPTION ANCIENT GLASS PLANT ASHES COBALT COLOR BLUE WINDOWS NICKEL 021001 nanoscience & nanotechnology Alkali metal HEXA Atomic and Molecular Physics and Optics 0104 chemical sciences Nickel chemistry Physical chemistry 0210 nano-technology Cobalt |
| Zdroj: | Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 188 (2018): 507–515. doi:10.1016/j.saa.2017.07.031 info:cnr-pdr/source/autori:Fornacelli, Cristina; Ceglia, Andrea; Bracci, Susanna; Vilarigues, Marcia/titolo:The role of different network modifying cations on the speciation of the Co2+ complex in silicates and implication in the investigation of historical glasses/doi:10.1016%2Fj.saa.2017.07.031/rivista:Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy (Print)/anno:2018/pagina_da:507/pagina_a:515/intervallo_pagine:507–515/volume:188 CIÊNCIAVITAE |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2017.07.031 |
| Popis: | In the last decades the speciation of the cobalt complex in a glass matrix has been extensively studied. Bivalent cobalt ions in glasses of different composition commonly adopt a tetrahedral coordination, though hexa-or penta-coordinated species are also possible. Changes in the absorbance spectrum of Co-doped glasses were attested in previous studies according to the introduction of different modifying cations. A shifting of the first sub-band characterizing the typical triplets of tetrahedral Co-2 ions in both the visible and near infrared regions was observed, but discrepancies in literature suggested a relevant role of glass composition on the definition of the optical signature,of cobalt. Co-doped glasses with different composition (soda-lime, potash-lime, mixed alkali and ZnO-Na2O-CaO-SiO2) were studied via Fiber Optic Reflectance Spectroscopy (FORS). Pseudo-Voigt functions were used for the deconvolution of the absorbance spectra and the features of the bands characteristic of each cobalt complex were investigated. The structural role played by each modifying cation and the fundamental implications of glass basicity on the speciation of different Co-complexes were stressed. Changes in glass structure resulted in different equilibria between the three absorbing species whose specific optical signatures in the 480-530 nm region interact to determine the resulting absorbance spectrum. (C) 2017 Elsevier B.V. All rights reserved. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect