beryllium

American  

[buh-ril-ee-uhm] / bəˈrɪl i əm /

noun

Chemistry.

1. a steel-gray, bivalent, hard, light, metallic element, the salts of which are sweet: used chiefly in copper alloys for better fatigue endurance, in springs, and in electrical contacts. Be; 9.0122; 4; 1.8 at 20° C.

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beryllium British  

/ bɛˈrɪlɪəm /

noun

1. Former names: glucinum.   glucinium.  a corrosion-resistant toxic silvery-white metallic element that occurs chiefly in beryl and is used mainly in X-ray windows and in the manufacture of alloys. Symbol: Be; atomic no: 4; atomic wt: 9.012; valency: 2; relative density: 1.848; melting pt: 1289°C; boiling pt: 2472°C

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beryllium Scientific  

/ bə-rĭl′ē-əm /

1. A hard, lightweight, steel-gray metallic element of the alkaline-earth group, found in various minerals, especially beryl. It has a high melting point and is corrosion-resistant. Beryllium is used to make sturdy, lightweight alloys and aerospace structural materials. It is also used as a neutron moderator in nuclear reactors. Atomic number 4; atomic weight 9.0122; melting point 1,278°C; boiling point 2,970°C; specific gravity 1.848; valence 2.

2. See Periodic Table

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Etymology

Origin of beryllium

1860–65; < Latin bēryll ( us ) beryl + -ium

Example Sentences

To generate the required beam, scientists accelerated Mo-92 ions and fired them at a beryllium target, producing fast moving Mo-86 nuclei.

From Science Daily • Mar. 8, 2026

An industrial hygiene firm found “serious and extensive” contamination by multiple toxins, including cyanide, lithium, lead, arsenic and beryllium, according to a report reviewed by The Times.

From Los Angeles Times • Jan. 7, 2026

Other elements found in Ukraine include beryllium and uranium, which are both crucial for nuclear weapons and reactors.

From BBC • Apr. 30, 2025

Specifically, the scientists compared a radiocarbon spike in those ancient tree rings with measurements of beryllium, an element found in Greenland ice cores that likewise provide records of ancient solar activity.

From Salon • Oct. 19, 2023

They had no trouble finding Lawrence’s 18-centimeter protons, but only in the lighter elements lithium and beryllium.

From "Big Science" by Michael Hiltzik