Barium chloride

Chembox new
Name = Barium chloride
ImageFile = Barium chloride.jpg
ImageSize = 200px
ImageName = Barium chloride
Section1 = Chembox Identifiers
CASNo = 10361-37-2
Section2 = Chembox Properties
Formula = BaCl₂ (anhydrous)
BaCl₂·2H₂O
MolarMass = 208.2324 g/mol
Appearance = White solid
Density = 3.856 g/cm³, solid
Solubility = 37.5 g/100 ml (26°C)
MeltingPt = 962 °C
BoilingPt = 1560 °C
Section3 = Chembox Structure
Coordination = 7-9
CrystalStruct = monoclinic or orthorhombic
Section4 = Chembox Thermochemistry
DeltaHf = −858.56 kJ/mol
Section7 = Chembox Hazards
EUClass = Toxic (T)
RPhrases = R20, R25
SPhrases = S1/2, S45
FlashPt = Non-flammable
Section8 = Chembox Related
OtherAnions = Barium fluoride
Barium bromide
Barium iodide
OtherCations = Calcium chloride
Strontium chloride
Lead chloride

Barium chloride is the ionic chemical compound with the formula BaCl₂. It is one of the most important water-soluble salts of barium. Like other barium salts, it is toxic and imparts a yellow-green coloration to a flame. It is also hygroscopic.

tructure and properties

BaCl₂ crystallizes in both the fluorite and lead chloride motifs, both of which accommodate the preference of the large Ba²⁺ ion for coordination numbers greater than six. [Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.] In aqueous solution BaCl₂ behaves as a simple salt; in water it is a 1:2 electrolyte and the solution exhibits a neutral pH.

Barium chloride reacts with sulfate ion to produce a thick white precipitate of barium sulfate.:BaCl₂(aq) + SO₄^2- → BaSO₄(s) + 2 Cl^-(aq)
Oxalate effects a similar reaction::BaCl₂(aq) + Na₂C₂O₄(aq) → BaC₂O₄ (s) + 2 NaCl(aq)

Preparation

Although inexpensively available, barium chloride can be prepared from barium hydroxide or barium carbonate, the latter being found naturally as the mineral witherite. These basic salts react with hydrochloric acid to give hydrated barium chloride. On an industrial scale, it is prepared via a two step process from barite (barium sulfate): [H. Nechamkin, "The Chemistry of the Element", McGraw-Hill, New York, 1968.] :BaSO₄ + 4 C → BaS + 4 COThis first step requires high temperatures.:BaS + CaCl₂ → BaCl₂ + CaSThe second step reqiures fusion of the reactants. The BaCl₂ can then be leached out from the mixture with water.

From water solutions of barium chloride, the dihydrate can be crystallized as white crystals: BaCl₂·2H₂O

Uses

As a cheap, soluble salt of barium, barium chloride finds wide application in the laboratory. It is commonly used as a test for sulfate ion (see chemical properties above). In industry, barium chloride is mainly used in the purification of brine solution in caustic chlorine plants and also in the manufacture of heat treatment salts, case hardening of steel, in the manufacture of pigments, and in the manufacture of other barium salts. BaCl₂ is also used in fireworks to give a bright green color. However, its toxicity limits its applicability. Barium Chloride is also used (with Hydrochloric acid) as a test for sulfates. When these two chemicals are mixed with a sulfate salt, a white precipitate forms, which is barium sulfate.

afety

Barium chloride, along with other water-soluble barium salts, is highly toxic. Sodium sulfate and Magnesium sulfate are potential antidotes because they form the insoluble solid barium sulfate BaSO₄, which is much less toxic.

References

*Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
* "Handbook of Chemistry and Physics", 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
* "The Merck Index", 7th edition, Merck & Co., Rahway, New Jersey, 1960.

External links

* [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc06/icsc0614.htm International Chemical Safety Card 0614] . ("anhydrous")
* [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc06/icsc0615.htm International Chemical Safety Card 0615] . ("dihydrate")
* [http://www.cdc.gov/niosh/npg/npgd0045.html NIOSH Pocket Guide to Chemical Hazards] .
* [http://ecb.jrc.it/ European Chemicals Bureau] .
* [http://www.solvayvishnubarium.com/products/bariumchloride/0,,4872-2-0,00.htm Barium chloride's use in industry] .