Barium bromide
- Brombarium
- Bromsaures barium
White solid
Fixed
4.781 g · cm -3
847 ° C
Well in water: 1041 g · l-1 (20 ° C)
Attention
0.5 mg · m-3
-757.3 KJ / mol
Template: Infobox chemical / molecular formula search available
Barium is a chemical compound of barium and one of the bromides. It is a colorless high-melting solid.
History
Barium plays a role in the discovery of radioactivity and nuclear fission. Since barium and radium compounds have similar properties, it is not easy to separate these. One possibility is the fractional crystallisation of suitable salts. First of all this the chlorides were used by Marie Curie. However, such a low rate and thus complex separation. Significantly better separations with higher Anreichungsraten allow the bromides.
This enrichment was important in the discovery of nuclear fission by Otto Hahn, as the product obtained in the irradiation of uranium with neutrons was initially held for radium. Only by the unexpected reaction in the fractional crystallization he and Fritz Strassmann discovered that it is radioactive barium isotopes and not radium, and that thus a nuclear fission takes place be had.
Production and representation
Hydrous barium bromide dihydrate precipitates upon concentration of barium and bromidhaltiger aqueous solutions. Above 120 ° C the crystal water is released and it forms the waterless salt.
Other possibilities for the recovery of barium are the reaction of barium carbonate or barium carbonate with hydrobromic acid.
Properties
Such as barium chloride and barium bromide barium iodide crystallized in the lead (II ) chloride structure.
In the gas phase barium bromide molecules, contrary to the predictions of the VSEPR model is not linear but bent with an angle of 146 °. Responsible for this are relativistic effects.
Use
Except for the separation of barium and radium, which is due to the hazard of the radioactive radium only of minor importance, barium is used for the production of chemicals for photography and for extraction of other bromides.