Rhenium

Rhenium • Transition Metal

Primary XPS region: Re4f
Overlapping regions: N/A
Binding energies of common chemical states:

Chemical state	Binding energy Re4f_7/2
Re metal	40.6 eV
Native oxide	41.7 eV

Experimental information

N/A

Interpretation of XPS spectra

Re4f region has well-separated spin-orbit components (Δ_metal=2.43eV).
- Broad loss feature for Re metal appears at ~53eV.
- Peaks in the Re4f region have an asymmetric peak shape for rhenium metal.
- Rhenium compounds, such as the oxide, have symmetric Re4f peaks.

About this element

Symbol: Re
Date of discovery: 1925
Name origin: Rhines, Germany
Appearance: silverish
Discoverer: Walter Noddack
Obtained from: gadolinite, molybdenite

Melting point: 3453 K
Boiling point: 5900 K
Density[kg/m³]: 21020
Molar volume: 8.86 × 10^-6 m³/mol
Protons/Electrons: 75
Neutrons: 111
Shell structure: 2,8,18,32,13,2
Electron configuration: [Xe]4f145d56s2
Oxidation state: 6,4,±2
Crystal structure: hexagonal

Rhenium, a silver, lustrous metal, has one of the highest melting points of all elements, with only tungsten and platinum being higher. Trace amounts of the element rhenium were discovered spectroscopically in platinum ores in the minerals columbite, gadolinite, molybdenite ,and in platinum ores by the German chemists I. Tacke-Noddack, W. Noddack, and O. C. Berg in 1925. The element is commercially used in powder form; however, rhenium can be solidified by pressing or resistance-sintering in a vacuum or hydrogen atmosphere, creating a contact shape. Rhenium is most often used in platinum-rhenium catalysts to make lead-free, high-octane gasoline and to make jet engine parts. The element is also used in flash lamps for photography and for filaments in mass spectrographs. Rhenium was the last naturally-occurring element to be discovered to date.