Barium

Characteristics

It is a alkaline-earth Métal soft silver plated which melts at high temperature. Is in nature in the form of barytine (BaSO₄), of benstonite (Ba, Sr) ₆ (CO₃) ₁₃ (Ca, Mg, mn) ₇-, of norséthite BaMg (CO₃) ₂, of sanbornite (BaSi₂O₅) and witherite (BaCO₃).

Its BaO oxide is called baryta or baryta anhydrous. One finds it mainly in the Barite also called barytine with equal quantity with barium sulfate. One does not find barium in the shape of native element because of his very great reactivity with the air.

Applications

It is used pure for the trapping of residual gases in the cathode tubes
Of small quantities of salts of this element (acetate, carbonate, chlorate, chloride, hydroxide, nitrate, oxide, perchlorate, peroxide, polysulfide, sulfate or sulphurize) are used in many manufacture, in particular:

of photographic paper
of glass
of painting
of Lubricant resistant at high temperature,
of ceramics, enamels and porcelains and their varnishes and Glaze S,
in Pyrotechny (gives the green color),
like darkening agent in Radiologie. In this last indication, considering strong toxicity in a dissolved state, one uses the sulfate, insoluble even in the acid medium of the Estomac.
in muds of Drilling.

It is also, in the form of titanate (BaTiO₃), one of the basic components of the piezoelectric Céramique S . The barium titanate is used inter alia for the insulating part of some condensing.
It is a component of the non-linear crystals (béta borate of barium), being in particular used to carry out mixtures of frequency in optics (non-linear Optique)

Dangerosity

To handle with precaution; it reacts with water by giving the Hydroxyde of barium Ba (OH) ₂, or baryta, which are very toxic and of which reactions with solvents, acids and oxidants are violent.

In case of doubt, consult the toxicological card of INRS n° 125:

External references

Barium titanate

See too

Simple: Barium

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