Barium chloride

Barium chloride
Identifiers
CAS number	10361-37-2 Y, 10326-27-9 (dihydrate)
EC number	233-788-1
RTECS number	CQ8750000 (anhydrous) CQ8751000 (dihydrate)
Properties
Molecular formula	BaCl2
Molar mass	208.23 g/mol (anhydrous) 244.26 g/mol (dihydrate)
Appearance	White solid
Density	3.856 g/cm3 (anhydrous) 3.0979 g/cm3 (dihydrate)
Melting point	962 °C
Boiling point	1560 °C
Solubility in water	31.2 g/100 mL (0 °C) 35.8 g/100 mL (20 °C) 59.4 g/100 mL (100 °C)
Solubility	soluble in methanol, insoluble in ethanol, ethyl acetate [1]
Structure
Crystal structure	orthogonal (anhydrous) monoclinic (dihydrate)
Coordination geometry	7-9
Thermochemistry
Std enthalpy of formation ΔfHo298	−858.56 kJ/mol
Hazards
MSDS	External MSDS
EU Index	056-004-00-8
EU classification	Toxic (T) Harmful (Xn)
R-phrases	R20, R25
S-phrases	(S1/2), S45
NFPA 704	0 2 0
Flash point	Non-flammable
Related compounds
Other anions	Barium fluoride Barium bromide Barium iodide
Other cations	Calcium chloride Strontium chloride Lead chloride
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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.

Structure 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.^[2] 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.

Ba²⁺(aq) + SO₄^2-(aq) → BaSO₄(s)

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):^[3]

BaSO₄ + 4 C → BaS + 4 CO

This first step requires high temperatures.

BaS + CaCl₂ → BaCl₂ + CaS

The second step requires 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.

Safety

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

References

1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
2. ^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
3. ^ H. Nechamkin, The Chemistry of the Element, McGraw-Hill, New York, 1968.

• 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

• International Chemical Safety Card 0614. (anhydrous)
• International Chemical Safety Card 0615. (dihydrate)
• NIOSH Pocket Guide to Chemical Hazards.
• European Chemicals Bureau.
• Barium chloride's use in industry.