barium

American  

[bair-ee-uhm, bar-] / ˈbɛər i əm, ˈbær- /

noun

Chemistry.

1. a whitish, malleable, active, divalent, metallic element, occurring in combination chiefly as barite or as witherite. Ba; 137.34; 56; 3.5 at 20°C.

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barium British  

/ ˈbɛərɪəm /

noun

1. a soft silvery-white metallic element of the alkaline earth group. It is used in bearing alloys and compounds are used as pigments. Symbol: Ba; atomic no: 56; atomic wt: 137.327; valency: 2; relative density: 3.5; melting pt: 729°C; boiling pt: 1805°C

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barium Scientific  

/ bâr′ē-əm /

1. A soft, silvery-white metallic element of the alkaline-earth group. It occurs only in combination with other elements, especially in barite. Barium compounds are used in x-raying the digestive system and in making fireworks and white pigments. Atomic number 56; atomic weight 137.33; melting point 725°C; boiling point 1,140°C; specific gravity 3.50; valence 2.

2. See Periodic Table

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Etymology

Origin of barium

First recorded in 1800–10; bar(ytes) + -ium

Example Sentences

The most concerning violations were linked to barium.

From Science Daily • Nov. 28, 2025

These are four endoscopy tests - upper endoscopy; lower endoscopy excluding colonoscopy; colonoscopy; and cystoscopy - and four radiology tests - CT scan; MRI scan; barium studies; and non-obstetric ultrasound.

From BBC • Nov. 25, 2025

The Environmental Protection Agency does not consider it a carcinogen; however, exposure to barium can cause gastrointestinal irritation, cardiovascular effects, kidney damage and respiratory problems.

From Los Angeles Times • May 4, 2025

At this time, the universe was made mostly of hydrogen and helium and very low abundances of other chemical elements, such as strontium and barium.

From Science Daily • May 14, 2024

She reminded him that parts of the city had been built on landfills containing arsenic, lead, mercury, barium, and other carcinogens.

From "Zeitoun" by Dave Eggers