ruthenium

American  

[roo-thee-nee-uhm, -theen-yuhm] / ruˈθi ni əm, -ˈθin yəm /

noun

Chemistry.

1. a steel-gray, rare metallic element, belonging to the platinum group of metals. Ru; 101.07; 44; 12.2 at 20°C.

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ruthenium British  

/ ruːˈθiːnɪəm /

noun

1. a hard brittle white element of the platinum metal group. It occurs free with other platinum metals in pentlandite and other ores and is used to harden platinum and palladium. Symbol: Ru; atomic no: 44; atomic wt: 101.07; valency: 0–8; relative density: 12.41; melting pt: 2334°C; boiling pt: 4150°C

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ruthenium Scientific  

/ ro̅o̅-thē′nē-əm /

1. A rare, silvery-gray metallic element that is hard, brittle, and very resistant to corrosion. It is used to harden alloys of platinum and palladium for jewelry and electrical contacts. Atomic number 44; atomic weight 101.07; melting point 2,310°C; boiling point 3,900°C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8.

2. See Periodic Table

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Etymology

Origin of ruthenium

1840–50; < New Latin, named after Ruthenia (from the fact that it was first found in ore from the region); -ium

Example Sentences

Manganese is more than 100,000 times more common on Earth than ruthenium, yet it has rarely been used successfully in photochemical systems.

From Science Daily • Nov. 26, 2025

Until now, many of these light-driven processes depended on ruthenium, osmium, or iridium -- elements that are costly, scarce, and create environmental concerns when mined.

From Science Daily • Nov. 26, 2025

This means their use has so far been confined to highly trained experts with specialised equipment, limiting the full adoption of ruthenium catalysis across industries.

From Science Daily • Apr. 8, 2024

"Almost every chemical, every plastic that we use on a day-to-day basis, came from a catalytic process, and many of these catalytic processes rely on precious metals like platinum, rhodium, ruthenium and others," Bayles said.

From Science Daily • Mar. 5, 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