barium oxide

chemical compound

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June 22, 2026

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Barium oxide (BaO) is a chemical compound derived from barium, an alkaline-earth metal. It is typically a white to grayish toxic powder. Barium oxide is obtained by heating barium carbonate or barium sulfate with carbon.1

It is used in various applications, including the production of barium hydroxide and barium peroxide, coating cathodes in electron tubes, and as a drying agent. Barium compounds, in general, are known for their density, a characteristic reflected in the name "barium" which comes from the Greek word for "heavy". All soluble barium compounds are toxic to mammals.12

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optics
Dispersion
…1884 it was discovered that barium oxide had the effect of raising the refractive index without increasing the dispersion, a property that proved to be of the greatest value in the design of photographic lenses known as anastigmats (lenses devoid of astigmatic aberration). In 1938 a further major improvement was…
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…1884 it was discovered that barium oxide had the effect of raising the refractive index without increasing the dispersion, a property that proved to be of the greatest value in the design of photographic lenses known as anastigmats (lenses devoid of astigmatic aberration). In 1938 a further major improvement was…
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crystal
Ionic bonds
…ionic binary crystals such as barium oxide (BaO), calcium sulfide (CaS), barium selenide (BaSe), or strontium oxide (SrO). They have the same structure as sodium chloride, with each atom having six neighbours. Oxygen can be combined with various cations to form a large number of ionically bonded solids.
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…ionic binary crystals such as barium oxide (BaO), calcium sulfide (CaS), barium selenide (BaSe), or strontium oxide (SrO). They have the same structure as sodium chloride, with each atom having six neighbours. Oxygen can be combined with various cations to form a large number of ionically bonded solids.
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