rhodium

American  

[roh-dee-uhm] / ˈroʊ di əm /

noun

Chemistry.

1. a silvery-white metallic element of the platinum family, forming salts that give rose-colored solutions: used to electroplate microscopes and instrument parts to prevent corrosion. Rh; 102.905; 45; 12.5 at 20°C.

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rhodium British  

/ ˈrəʊdɪəm /

noun

1. a hard corrosion-resistant silvery-white element of the platinum metal group, occurring free with other platinum metals in alluvial deposits and in nickel ores. It is used as an alloying agent to harden platinum and palladium. Symbol: Rh; atomic no: 45; atomic wt: 102.90550; valency: 2–6; relative density: 12.41; melting pt: 1963±3°C; boiling pt: 3697±100°C

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rhodium Scientific  

/ rō′dē-əm /

1. A rare, silvery-white metallic element that is hard, durable, and resistant to acids. It is used as a permanent plating for jewelry and is added to platinum to make high-temperature alloys. Atomic number 45; atomic weight 102.905; melting point 1,966°C; boiling point 3,727°C; specific gravity 12.41; valence 2, 3, 4, 5, 6.

2. See Periodic Table

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Etymology

Origin of rhodium

From New Latin, dating back to 1804; see origin at rhod-, -ium

Example Sentences

See Examples For:

rhodium

Platinum, palladium and rhodium are key components of autocatalysts that reduce harmful emissions from internal combustion engines.

From The Wall Street Journal ● Jun. 30, 2026

These critical emission-control devices are valuable because they contain rare metals, like palladium and rhodium, that can be extracted and resold.

From New York Times ● May 27, 2024

The catalytic converter, an exhaust emission control device typically found in the undercarriage of a vehicle, contains precious metals including rhodium, palladium and platinum.

From Los Angeles Times ● May 26, 2024

But demand will inevitably go back up once the prices of rhodium, palladium and platinum — metals used in the manufacture of catalytic converters — rise again, law enforcement officials and lawmakers say.

From Seattle Times ● Apr. 1, 2024

This substance is always native—it is always in the metallic state; and the metals with which it is found connected, and which are rarely found elsewhere, are palladium, rhodium, iridium, osmium, and ruthenium.

From The Chemical History of a Candle by Crookes, William, Sir