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); see -ium

Example Sentences

Many widely used photocatalyst metals, including ruthenium and iridium, are scarce and expensive.

From Science Daily • Feb. 27, 2026

By adjusting the ligands and ions arranged around the ruthenium molecules, they demonstrated that a single device can display many different dynamic responses.

From Science Daily • Jan. 3, 2026

The researchers synthesized 17 carefully designed ruthenium complexes and studied how small changes in molecular shape and the surrounding ionic environment influence electron behavior.

From Science Daily • Jan. 3, 2026

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

Earth needed steel, tin, nickel, and zinc; more than anything, Earth needed ruthenium, the rare-earth catalyst that made the huge solar energy converters possible.

From Gold in the Sky by Llewellyn