Manganese • Transition Metal
Primary XPS region: Mn2p
Overlapping regions: Cu LMM, Au4p1/2
Binding energies of common chemical states:
| Chemical state | Binding energy Mn2p3/2 / eV |
|---|---|
| Mn metal | 638.7 |
| MnO | 641.4 |
| Mn2O3 | 641.4 |
| MnO2 | 641.8 |
Experimental Information
- Collect Mn3s region to enable straightforward identification of Mn oxidation state. •
- Some compounds/alloys of manganese are magnetic.
- Degauss samples if possible before analysis.
Interpretation of XPS spectra
- Mn2p peak has significantly split spin-orbit components (Δmetal=11.2eV).
- Mn2p peaks have asymmetric shape for metal.
- Mn oxide peaks are significantly shifted to higher binding energy than the metal.
- A well resolved Mn2p spectrum for metal shows multiplet splitting.[1]
- Second component (shifted by 0.9eV from main peak) can be neglected when fitting mixed oxide/metal spectra.
- Method for chemical analysis of Mn oxides.
- Mn2p peaks for Mn oxides have many multiplet-split components, similar to the Cr2p region in chromium oxides.
- MnO2 has a much narrower Mn2p3/2 peak compared to MnO or Mn2O3.
- Also has an identifiable shape at the top of the Mn3/2 peak.
- MnO has a satellite feature (~647 eV), which is not present for either Mn2O3 or MnO2 .
- Possible to distinguish Mn oxidation states using Mn3s peak.
- This peak has two, multiplet split components.
- Caused by coupling of non-ionized 3s electron with 3d valence-band electrons.
- Magnitude of peak splitting is diagnostic of oxidation state.
- ΔE for MnO (Mn2+) 6.0eV, Mn2O3 (Mn3+) ≥ 5.3eV, MnO2 (Mn4+) 4.7eV
- This peak has two, multiplet split components.
References
- [1] MC Biesinger et al., Applied Surface Science 257 (2011) 2717-2730.
About This Element
Symbol: Mn
Date of Discovery: 1774
Name Origin: Latin magnes
Appearance: silverish/grayish
Discoverer: Johann Gahn
Obtained From: brine, sea water
Melting Point: 1519 K
Boiling Point: 2334 K
Density[kg/m3]: 7470
Molar Volume: 7.35 × 10-6 m3/mol
Protons/Electrons: 25
Neutrons: 30
Shell Structure: 2,8,13,2
Electron Configuration: [Ar]3d54s2
Oxidation State: 7,6,4,2,3
Crystal Structure: Cubic Body Centered
Manganese is used in the same disciplines today as it was in prehistoric times. Used in iron and steel production, it was found in iron ores forged by the Spartans. The Egyptians and Romans used manganese compounds to add or remove color from glass. Manganese compounds can color glass an amethyst color and produce the color of the gemstone amethyst. Most of the world’s deposits of manganese are found in South Africa and Ukraine. Manganese also exists in nodules on the ocean floor, however no economical method of harvesting them has been found. Potassium permanganate (KMnO4) is commonly used in laboratories for its oxidizing properties.
Application Notes
