|Name: barium||Group number: 2|
|Symbol: Ba||Group name: Alkaline earth metal|
|Atomic number: 56||Period number: 6|
|Atomic weight: 137.327 (7)||Block: s-block|
|CAS Registry ID: 7440-39-3||Voice: |
|Standard state: solid at 298 K||Colour: silvery white|
|Classification: Metallic||Availability: |
Image adapted with permission from Prof James Marshall"s (U. North Texas, USA) Walking Tour of the elements CD.
Barium is a metallic element, soft, and when pure is silvery white like lead. The metal oxidises very easily and it reacts with water or alcohol. Barium is one of the alkaline-earth metals. Small amounts of barium compounds are used in paints and glasses.
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|The picture above shows the result of adding different metal salts to a burning reaction mixture of potassium chlorate and sucrose. The red colour originates from strontium sulphate. The orange/yellow colour originates from sodium chloride. The green colour originates from barium chlorate. The blue colour originates from copper (I) chloride. The lilac colour that should be evident from the potassium chlorate is washed out by the other colours, all of which are more intense. Do not attempt this reaction unless are a professionally qualified chemist and you have carried out a legally satisfactory hazard assessment. Improperly done, this reaction is dangerous! Select a movie icon to see flame burning in from right to left.|
Barium salts impart green colours to flames. The picture above shows the colour arising from adding barium chlorate (BaClO3) to a burning mixture. Do not attempt this reaction unless are a professionally qualified chemist and you have carried out a legally satisfactory hazard assessment.
IsolationHere is a brief summary of the isolation of barium.
Barium metal is available commercially and there is normally no need to make it in the laboratory. Commercially, it is made on small scale by the electrolysis of molten barium chloride, BaCl2.
cathode: Ba2+(l) + 2e- Baanode: Cl-(l) 1/2Cl2 (g) + e-
Barium metal can also be islated from the reduction of barium oxide, BaO, with aluminium.
6BaO + 2Al 3Ba + Ba3Al2O6