osmium

American  

[oz-mee-uhm] / ˈɒz mi əm /

noun

Chemistry.

1. a hard, heavy, metallic element having the greatest density of the known elements and forming octavalent compounds, as OsO 4 and OsF 8 : used chiefly as a catalyst, in alloys, and in the manufacture of electric-light filaments. Os; 190.2; 76; 22.57.

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osmium British  

/ ˈɒzmɪəm /

noun

1. a very hard brittle bluish-white metal occurring with platinum and alloyed with iridium in osmiridium: used to produce platinum alloys, mainly for pen tips and instrument pivots, as a catalyst, and in electric-light filaments. Symbol: Os; atomic no: 76; atomic wt: 190.2; valency: 0 to 8; relative density: 22.57; melting pt: 3033±30°C; boiling pt: 5012±100°C

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osmium Scientific  

/ ŏz′mē-əm /

1. A hard, brittle, bluish-white metallic element that is the densest naturally occurring element. It is used to make very hard alloys for fountain pen points, electrical contacts, and instrument pivots. Atomic number 76; atomic weight 190.2; melting point 3,000°C; boiling point 5,000°C; specific gravity 22.57; valence 2, 3, 4, 8.

2. See Periodic Table

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Etymology

Origin of osmium

1795–1805; < New Latin < Greek osm ( ḗ ) smell + -ium -ium; named from the penetrating odor of one of its oxides

Example Sentences

The results showed a moderate increase in activity, but the dissolution of osmium had a detrimental effect, significantly compromising the structural integrity of iridium and ruthenium.

From Science Daily • Nov. 3, 2023

While brilliant, Kolnai’s writing has the density of osmium.

From New York Times • Dec. 27, 2021

For secondary fixation, we used 2% osmium tetroxide in 1.25% sodium bicarbonate for 2–3 h at room temperature.

From Nature • May 20, 2014

Or osmium — atomic weight: 190.2 — for that matter?

From Scientific American • Mar. 8, 2012

So with iridium and rhodium, and osmium and ruthenium, which are so closely allied that they make pairs, being separated each from its own group.

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