The name barium originates from the alchemical derivative "baryta", from Greek βαρὺς (barys), meaning 'heavy'.

Historically, it was used as a getter for vacuum tubes and in oxide form as the emissive coating on indirectly heated cathodes.

It is a component of YBCO (high-temperature superconductors) and electroceramics, and is added to steel and cast iron to reduce the size of carbon grains within the microstructure.

[9]: 2 At room temperature and pressure, barium metal adopts a body-centered cubic structure, with a barium–barium distance of 503 picometers, expanding with heating at a rate of approximately 1.8×10−5/°C.

Sulfuric acid is a notable exception because passivation stops the reaction by forming the insoluble barium sulfate on the surface.

[12] Barium combines with several other metals, including aluminium, zinc, lead, and tin, forming intermetallic phases and alloys.

Johan Gottlieb Gahn also isolated barium oxide two years later in similar studies.

Oxidized barium was at first called "barote" by Guyton de Morveau, a name that was changed by Antoine Lavoisier to baryte (in French) or baryta (in Latin).

Also in the 18th century, English mineralogist William Withering noted a heavy mineral in the lead mines of Cumberland, now known to be witherite.

[18] Davy, by analogy with calcium, named "barium" after baryta, with the "-ium" ending signifying a metallic element.

[19][20] The production of pure oxygen in the Brin process was a large-scale application of barium peroxide in the 1880s, before it was replaced by electrolysis and fractional distillation of liquefied air in the early 1900s.

If the quartz penetrates too deeply into the ore, or the iron, zinc, or lead content is abnormally high, then froth flotation is used.

The product is a 98% pure baryte (by mass); the purity should be no less than 95%, with a minimal content of iron and silicon dioxide.

[9]: 3  Commonly sold barium is about 99% pure, with main impurities being strontium and calcium (up to 0.8% and 0.25%) and other contaminants contributing less than 0.1%.

[28] There is little depletion of barium concentrations in the upper ocean for an ion with a nutrient-like profile, thus lateral mixing is important.

[9]: 4  Barium is suitable for this purpose because of its low vapor pressure and reactivity towards oxygen, nitrogen, carbon dioxide, and water; it can even partly remove noble gases by dissolving them in the crystal lattice.

This application is gradually disappearing due to the rising popularity of the tubeless LCD, LED, and plasma sets.

[9]: 4 Other uses of elemental barium are minor and include an additive to silumin (aluminium–silicon alloys) that refines their structure, as well as[9]: 4 Barium sulfate (the mineral baryte, BaSO4) is important to the petroleum industry as a drilling fluid in oil and gas wells.

[10]: 4–5  The precipitate of the compound (called "blanc fixe", from the French for "permanent white") is used in paints and varnishes; as a filler in ringing ink, plastics, and rubbers; as a paper coating pigment; and in nanoparticles, to improve physical properties of some polymers, such as epoxies.

[35] Global ocean circulation reveals a strong correlation between dissolved barium and silicic acid.

[36] With both dissolved and particulate barium's links with silicic acid and POC, it can be used to determine historical variations in the biological pump, carbon cycle, and global climate.

[36] The barium particulate barite (BaSO4), as one of many proxies, can be used to provide a host of historical information on processes in different oceanic settings (water column, sediments, and hydrothermal sites).

Symptoms include "convulsions... paralysis of the peripheral nerve system ... severe inflammation of the gastrointestinal tract".

Inhaled dust containing insoluble barium compounds can accumulate in the lungs, causing a benign condition called baritosis.