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Barium: The Element

Barium: The Element

Did you know that barium is a chemically active metal which can ignite spontaneously when exposed to moist air?
Abhijit Naik
Barium is a heavy chemical element, with the symbol Ba and atomic number 56. This soft, silvery alkaline earth metal is never found in its purest form in the nature, mainly because of its high reactivity to air. It is kept either in petroleum-based fluids or oxygen-free liquids to restrain it from being oxidized. Barium peroxide, barium chloride, chlorate, sulfate, etc., are some of the major compounds of this chemical element. In fact, barium sulfate and barium carbonate are the most common naturally occurring minerals.

Some Facts about Barium

Barium is found in mineral barite, which is crystallized barium sulfate. The word 'barium' is derived from the Greek word, Bary, meaning heavy. It was identified by a Swedish pharmaceutical chemist, Carl Scheele in 1774, and scientifically obtained by British chemist, Sir Humphry Davy in 1808. Barite being insoluble, cannot be used directly to produce other compounds; therefore, the ore is heated with carbon to reduce the content of barium sulfide in it. Various compounds of this element are formed by hydrolyzing or reacting it with other acids. These include barium chloride, barium carbonate, and barium nitrate.

Characteristics
  • It is difficult to obtain barium in its purest form because of its tendency to oxidize in air.
  • Barium, though chemically similar to calcium, is much more reactive than calcium.
  • It is the 14th most abundant element on the planet.
  • It has a boiling point of 1640°C and a melting point of 725°C.
  • It oxidizes readily when exposed to air and ignites spontaneously when exposed to moist air.
  • It reacts with water or alcohol to produce hydrogen.
  • If burned in presence of air or oxygen, it produces barium oxide and peroxide.
  • Barium compounds have high specific gravity of 3.5 at 20°C.
  • All the compounds of barium, which are soluble in water or acid are poisonous.
Uses
  • Barium compounds are used extensively in petroleum industry.
  • Barite is used as a drilling fluid for drilling boreholes into the Earth's crust.
  • Barium enema is used as a radiocontrast agent in x-ray imaging of the digestive system.
  • Coating the electrodes of fluorescent lamps with barium oxide eases the release of electrons.
  • This metal is used to take out the last traces of oxygen in vacuum tubes.
  • Barium carbonate is used in cement, bricks, glass making, and rat poison.
  • Barite is an important component of the rubber production industry.
  • The green color that appears during the display of fireworks is attributed to the presence of barium nitrate in them.
  • When welding rail track together, barium peroxide is used as a catalyst to initiate an aluminothermic reaction.
  • Barium fluoride, a chemical compound of barium and fluorine, is used to make optics in infra-red applications.
  • Barium is an important component of high temperature yttrium barium copper oxide superconductors.
Effect on Humans
When taken in low doses, barium works as a muscle stimulant. However, higher doses block the potassium ion channels essential for the proper functioning of nervous system, thus triggering an adverse effect in the nervous system, causing cardiac problems, weakness, paralysis, and anxiety. It is possible to take it orally, because like other heavy metals, it doesn't accumulate within the bodies of living organisms. Being highly insoluble, it is easily eliminated through the digestive tract. However, if inhaled in the form of dust or gas, it can get accumulated in the lungs and cause baritosis―a benign type of pneumoconiosis.

Since its discovery in the first half of the 19th century, barium has become an important constituent of most of the industries today. It has become very difficult to substitute this metal with an equally dominant counterpart.