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Title: Vanadium Electronic Configuration Determination From L2,3 Transition in V-oxide Compounds and Roscoelite
Abstract 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.  more » « less
Award ID(s):
2045277
PAR ID:
10414846
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Microscopy and Microanalysis
Volume:
29
Issue:
2
ISSN:
1431-9276
Page Range / eLocation ID:
459 to 469
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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