Barium

Appearance

Melting and Boiling points

Melting point:

727 C, 1340.6 F, 1000.15 K

Boiling point:

1845 C, 3353 F, 2118.15 K

A soft silvery metal that rapidly tarnishes in air and reacts with water. ‘Barium meal’ and ‘barium enemas’ (barium sulfate) are given to patients suffering from digestive disorders : the action of the stomach and intestines can be seen as the metal’s progress through the body is revealed by X-rays. Most barium sulfate is now used in drilling fluids for oil and gas wells, and several million tonnes a year are manufactured.

The uses of Barium

Interesting Facts

History

Barium is not an extensively used element. The best-known use is in the form of barium sulfate, which can be drank as a medical cocktail to outline the stomach and intestines for medical examination. The sulfate is also used in paint and in glass making. Barium carbonate has been used as a rat poison. Barium nitrate gives fireworks a green color.

Sir Humphry Davy discovered barium in 1808

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Its name comes from the Greek word meaning "heavy."

Ancient alchemists experimented with barium minerals.

Barium in barite mineral form was part of ancient witchcraft or folklore because the stones would glow after exposure to light.

Barium readily oxidizes in air to produce a dark gray coating.

It reacts exothermically with water to release hydrogen gas.

Barium was identified as an element in barite by Carl Scheele in 1774, but he could not isolate it.

Barium makes up about 0.0425% of the Earth's crust.

It is found on the oceans at around thirteen micrograms per liter.

In the early 1600s, Vincenzo Casciarolo, of Bologna, Italy, found some unusual pebbles. If they were heated to redness during the day, they would shine during the night. This was the mineral barite (barium sulfate, BaSO4). When Bologna stone, as it became known, was investigated by Carl Scheele in 1760s he realised it was the sulfate of an unknown element. Meanwhile a mineralogist, Dr William Withering, had found another curiously heavy mineral in a lead mine in Cumberland which clearly was not a lead ore. He named it witherite; it was later shown to be barium carbonate, BaCO3. Neither the sulfate nor the carbonate yielded up the metal itself using the conventional process of smelting with carbon. However, Humphry Davy at the Royal Institution in London produced it by the electrolysis of barium hydroxide in 1808.

Biological Role

Natural Abundance

Barium and all its compounds that are water or acid soluble are toxic.

Barium occurs only in combination with other elements, chiefly in the ores barytes and witherite. It can be prepared by electrolysis of the chloride, or by heating barium oxide with aluminum.

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Barium

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