Manganese

Manganese • Transition Metal

Primary XPS region: Mn2p
Overlapping regions: Cu LMM, Au4p_1/2
Binding energies of common chemical states:

Chemical state	Binding energy Mn2p_3/2
Mn metal	638.7 eV
MnO	641.4 eV
Mn₂O₃	641.4 eV
MnO₂	641.8 eV

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 (Δ_metal=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.

High Resolution Mn2p3/2 Spectrum Manganese Metal

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 Mn2p_3/2 peak compared to MnO or Mn₂O₃.
  - Also has an identifiable shape at the top of the Mn2p_3/2 peak.
- MnO has a satellite feature (~647eV), which is not present for either Mn₂O₃ or MnO₂.

It is 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.

References

[1] MC Biesinger et al., Applied Surface Science 257 (2011) 2717-2730.

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Table of elements

About the 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.

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