Rhodium

Rhodium • Transition Metal

Primary XPS region: Rh3d
Overlapping regions: Mg KLL
Binding energies of common chemical states:

Chemical state	Binding energy Rh3d_5/2
Rh metal	307.6 eV
Native oxide	308.8 eV

Experimental information

N/A

Interpretation of XPS spectra

Rh3d region has well-separated spin-orbit components (Δmetal=4.7eV).
- The Coster-Kronig effect is observed, broadening the Rh3d3/2 component compared to Rh3d5/2, and making the Rh3d3/2 component shorter than expected.
There is a very strong overlap between the Ru3d and C1s regions.
- RhO₂ may also have asymmetric peak shapes in some crystalline phases [1].

Reference

[1] Y. Abe et al., Surface Science Spectra, Vol. 8, No. 2, 2001.

About this element

Symbol: Rh
Date of discovery: 1803
Name origin: Greek rhodon
Appearance: silver-white
Discoverer: William Wollaston
Obtained from: platinum ores

Melting point: 2237 K
Boiling point: 3968 K
Density[kg/m³]: 12450
Molar volume: 8.28 × 10^-6 m³/mol
Protons/Electrons: 45
Neutrons: 58
Shell structure: 2,8,18,16,1
Electron configuration: [Kr]4d85s1
Oxidation state: 2,3,4
Crystal structure: cubic

This silvery-white hard transition metal belongs to the platinum group. It has high reflectance and is hard and durable. Rhodium is primarily used as an alloying agent with platinum and iridium to improve high temperature strength and oxidatlion resistance. These metal alloys are employed in furnace windings, electrical contacts, and high temperature resistance wires. As the pure metal, rhodium’s brilliance and resistance to tarnish makes it well suited for plating jewelry. This metal was discovered in 1803 by W. Wollaston and is named from the Greek origin "rhono", meaning rose, after the rosy-colored solution yielded by its salts.