Vanadium Electronic Configuration Determination From L2,3 Transition in V-oxide Compounds and Roscoelite
| Autor: | Pierre-Marie Zanetta, Maxwell S Drexler, Isabel F Barton, Thomas J Zega |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Microscopy and Microanalysis. 29:459-469 |
| ISSN: | 1435-8115 1431-9276 |
| DOI: | 10.1093/micmic/ozac057 |
| Popis: | We report on the electronic structure of vanadium in synthetic V-oxides and in natural roscoelite (V-rich phyllosilicate). This study applied electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM), combined with first-principle calculations, to (1) establish relationships between the V oxidation state and EELS L2,3 features and (2) better constrain the oxidation state and crystallographic siting of V in roscoelite, with implications for other V-bearing phyllosilicates. Both EELS measurements and band structure calculations show that the EELS L2/L3 ratio increases as the oxidation state of V increases. We establish a quantitative relationship between the V L2,3 near-edge structure and the V oxidation state by normalizing the L2 maximum peak intensity to the L3 peak intensity. By applying this method to roscoelite, we find that it hosts a mix of trivalent and tetravalent V distributed between the octahedral and tetrahedral sites with a V4+/ΣV = 0.6 ± 0.1. This relationship is applicable to measurements of V oxidation states in oxide and phyllosilicate minerals, which is useful for constraining the conditions of rock and mineral formation and has potential implications for metal extraction from phyllosilicate ores. |
| Databáze: | OpenAIRE |
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