Boron oxide:Uses,Production,Reactions

Boron oxide is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria.It has many important industrial applications, chiefly in ceramics as a flux for glazes and enamels and in the production of glasses.  

Production

Boron oxide is produced by treating borax with sulfuric acid in a fusion furnace. At temperatures above 750℃, the molten boron oxide layer separates out from sodium sulfate. It is then decanted, cooled and obtained in 96%-97% purity. Another method is heating boric acid above B300℃. 

Boric acid will initially decompose into steam (H2O(g)) and metaboric acid (HBO2) at around 170℃, and further heating above 300℃ will produce more steam and diboron trioxide. The reactions are: 

H3BO3→HBO2+H2O and 2HBO2→B2O3 + H2O

Boron monoxide (B2O) is a chemical compound of boron and oxygen. Two experimental studies have proposed existence of diamond-like and graphite-like B2O, as for boron nitride and carbon solids. However, a later, systematic, experimental study of boron oxide phase diagram suggests that B2O is unstable.

Reactions

Molten boron oxide attacks silicates. Containers can be passivated internally with a graphitized carbon layer obtained by thermal decomposition of acetylene.

Uses

Major component of borosilicate glass;

Fluxing agent for glass and enamels;

Starting material for synthesizing other boron compounds such as boron carbide;

An additive used in glass fibres (optical fibres);

The inert capping layer in the Liquid Encapsulation Czochralski process for the production of gallium arsenide single crystal;

As an acid catalyst in organic synthesis.

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