Orbitals and Energies #
Note – these are listed in BINDING ENERGY
Re 4f ≈ 40 eV
Re 4s ≈ 625 eV
Re 4p ≈ 445 eV
Re 4d ≈ 260 eV
Common Overlaps for Re 4f #
W 5p – Os 4f – Rh 4p – Mn 3p – Ne 2s – Ca 3s – Ru 4p – Th 6p – Te 4d – As 3d – At 5d – Y 4s – Cr 3p – I 4d
Theory and Background #
Typically considered to be one of the most stable elements due to its high melting and boiling points, rhenium is often found in nickel based superalloys, but also finds use in olefin metathesis and reforming catalysis. Rhenium can exhibit multiple oxidation states, with +7, +6, +4 and +2 the most common in materials analysed by XPS.
Experimental Advice #
High valence rhenium oxides can undergo disproportionation during XPS analysis [1], so a suitable methodology, such as rapid acquisition and recording the Re(4f) region first and again at the end should be considered.
Data Analysis Guidance #
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References #
[1] S. Iqbal, M. L. Shozi and D. J. Morgan, X‐ray induced reduction of rhenium salts and supported oxide catalysts, Surf. Inter. Anal. 49 (2017) 223-226. Read it online here
[2] Measured at HarwellXPS on a Thermo K-Alpha+ spectrometer, which has been calibrated using the internal ISO calibration method.
[3] Average of measurements from NIST. NIST Standard Reference Database 20, Version 4.1, Visit the site
