Vanadium is usually present as the VO2+ ion in fossil fuels. Because of its paramagnetic state (S = 1/2, I = 7/2), several electron paramagnetic resonance (EPR) studies of VO2+ in fossil fuels have been reported. One important conclusion mentioned in some studies is that EPR is not a good analytical technique for studying vanadium in fossil fuels. Another conclusion is that vanadium complexes are present in two structurally different forms, each dominating at different temperatures. On chemical grounds, however, such behavior for VO2+ complexes is unexpected. We have reexamined the literature data and find that several of the above discrepances can be traced to the earlier analysis procedures. A critique of earlier vanadium EPR studies and details of our new results will be presented.
- Electron paramagnetic resonance spectroscopy
- Fossil fuels
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