Barium Oxide

The most common use of the substance "barium oxide" is based on its property of hygroscopicity - the ability to absorb water. That is why it is used directly in chemical production as a component for the production of barium peroxide. In industry, oxide is indispensable in the manufacture of ceramic magnets. In addition, in modern conditions, barium oxide, the formula of which BaO, has found great application in microelectronics and electrical engineering. Barium ferrate is used for the production of magnetoceramics, which is obtained by joining in a powerful magnetic field under the press of a mixture of powders of barium and iron oxides.

However, the main direction of application is the production of thermionic cathodes. At the beginning of the last century, a scientist from Germany, Venelt, was studying the law of electron emission, which was recently discovered by the British researcher Richardson. For experiments, Venelt used pieces of platinum wire. The first experimental results completely confirmed the conclusions made subsequently by the English physicist. But then the experiment failed, and Venelt suggested that the electron flux is much higher than normal because there could be some impurities on the surface of the working substance-platinum. Verified his assumption, Venelt established that the source of the deviation of the electron flux is barium oxide, which got to the surface of platinum as part of the lubrication of technical devices used in the experiment. The conclusions of Venelt remained unrecognized for a long time, because the learned community could not experimentally reproduce his experience. It took almost a hundred years for the English physicist Kohler to prove that he was right. Kohler on the basis of multiple experiments has proved that if barium oxide is subjected to gradual heating at low pressure, then the intensity of thermionic emission rises rapidly.

Only in the thirties of the last century the German chemist Paul suggested that the electrons are activated precisely because of the presence of an admixture of barium in the oxide. During the reaction, which is carried out at low pressure, some of the oxygen is volatilized from the oxide. The remaining barium ionizes and thus contributes to the appearance of free electrons. These electrons were the ones that left the crystal structure when heated and which Venelt had once observed.

And it was only at the beginning of the second half of the last century that the validity of this hypothesis was finally proved. Chemists A. Bundel and P. Kovtun (USSR) were able not only to numerically determine the concentration of impurities of barium in the oxide, but also to compare experimentally its value with the value of the thermoemission flux. That is why barium oxide is used as an active substance in the manufacture of thermionic cathodes. An example is the electron beam, which creates an image on the screen of a simple TV or computer monitor. As the source of the stream, barium oxide acts here.

If this substance is tried to dissolve in water, then it is found that barium oxide reacts with water when the solution is heated. This produces a barium hydroxide , a white powder with a melting point of 78 ° C. This compound perfectly interacts with carbon dioxide, and therefore an aqueous solution, often called "barite water", is widely used as a reagent for carbon dioxide.

As a starting and necessary component, the compound is a part of various coloring materials, lubricants and oils. This use of barium oxide was predicted by D.I. Mendeleev.