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It's Elemental

The Element Rhodium

[Click for Isotope Data]


45 Rh Rhodium 102.90550

Atomic Number: 45

Atomic Weight: 102.90550

Melting Point: 2237 K (1964°C or 3567°F)

Boiling Point: 3968 K (3695°C or 6683°F)

Density: 12.4 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 5

Group Number: 9

Group Name: none

What's in a name? From the Greek word for rose, rhodon.

Say what? Rhodium is pronounced as RO-dee-em.

History and Uses:

Rhodium was discovered by William Hyde Wollaston, an English chemist, in 1803 shortly after his discovery of the element palladium. He obtained rhodium from a sample of platinum ore that was obtained from South America. After removing the platinum and palladium from the sample, he was left with a dark red powder. The powder turned out to be sodium rhodium chloride (Na3RhCl6·12H2O). Wollaston obtained rhodium from the powder by treating it with hydrogen gas (H2). Rhodium tends to occur along with deposits of platinum and is primarily obtained as a byproduct of mining and refining platinum. Rhodium is also obtained as a byproduct of the nickel mining operation in the Sudbury region of Ontario, Canada.

Rhodium is used to make electrical contacts, as jewelry and in catalytic converters, but is most frequently used as an alloying agent in other materials, such as platinum and palladium. These alloys are used to make such things as furnace coils, electrodes for aircraft spark plugs and laboratory crucibles.

Estimated Crustal Abundance: 1×10-3 milligrams per kilogram

Estimated Oceanic Abundance: Not Applicable

Number of Stable Isotopes: 1 (View all isotope data)

Ionization Energy: 7.459 eV

Oxidation States: +3

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d8


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For questions about this page, please contact Steve Gagnon.