Barium chloride

Barium chloride
Names
	Other names Barium muriate; Muryate of Barytes[1]; Barium dichloride
Identifiers
CAS Number	10361-37-2 ; 10326-27-9 (dihydrate) ;
3D model (JSmol)	Interactive image;
ChemSpider	23540 ;
ECHA InfoCard	100.030.704
EC Number	233-788-1;
PubChem CID	25204;
RTECS number	CQ8750000 (anhydrous) ; CQ8751000 (dihydrate);
UNII	0VK51DA1T2 ; EL5GJ3U77E (dihydrate) ;
UN number	1564
CompTox Dashboard (EPA)	DTXSID7044508 ;
	InChI InChI=1S/Ba.2ClH/h;21H/q+2;;/p-2 Key: WDIHJSXYQDMJHN-UHFFFAOYSA-L ; InChI=1/Ba.2ClH/h;21H/q+2;;/p-2 Key: WDIHJSXYQDMJHN-NUQVWONBAL;
	SMILES [Ba+2].[Cl-].[Cl-];
Properties
Chemical 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 (1,764 °F; 1,235 K) (960 °C, dihydrate)
Boiling point	1,560 °C (2,840 °F; 1,830 K)
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[2]
Magnetic susceptibility (χ)	-72.6·10−6 cm3/mol
Structure
Crystal structure	orthogonal (anhydrous) ; monoclinic (dihydrate)
Coordination geometry	7-9
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	−858.56 kJ/mol
Hazards
Main hazards	Toxic if ingested
Safety data sheet	See: data page; NIH BaCl
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H301, H332
GHS precautionary statements	P261, P264, P270, P271, P301+310, P304+312, P304+340, P312, P321, P330, P405, P501
NFPA 704 (fire diamond)	0 3 0
Flash point	Non-flammable
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	78 mg/kg (rat, oral); 50 mg/kg (guinea pig, oral)[3]
LDLo (lowest published)	112 mg Ba/kg (rabbit, oral); 59 mg Ba/kg (dog, oral); 46 mg Ba/kg (mouse, oral)[3]
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.5 mg/m3[4]
REL (Recommended)	TWA 0.5 mg/m3[4]
IDLH (Immediate danger)	50 mg/m3[4]
Related compounds
Other anions	Barium fluoride; Barium bromide; Barium iodide
Other cations	Beryllium chloride; Magnesium chloride; Calcium chloride; Strontium chloride; Radium chloride; Lead chloride
Supplementary data page
Structure and; properties	Refractive index (n),; Dielectric constant (εr), etc.
Thermodynamic; data	Phase behaviour; solid–liquid–gas
Spectral data	UV, IR, NMR, MS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	verify (what is ?)
	Infobox references

Barium chloride is an inorganic compound with the formula Ba Cl₂. It is one of the most common water-soluble salts of barium. Like most other barium salts, it is white, toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting first to the dihydrate BaCl₂(H₂O)₂. It has limited use in the laboratory and industry.[5]

Structure and properties

BaCl₂ crystallizes in two forms (polymorphs). One form has the cubic fluorite (CaF₂) structure and the other the orthorhombic cotunnite (PbCl₂) structure. Both polymorphs accommodate the preference of the large Ba²⁺ ion for coordination numbers greater than six.[6] The coordination of Ba²⁺ is 8 in the fluorite structure[7] and 9 in the cotunnite structure.[8] When cotunnite-structure BaCl₂ is subjected to pressures of 7–10 GPa, it transforms to a third structure, a monoclinic post-cotunnite phase. The coordination number of Ba²⁺ increases from 9 to 10.[9]

In aqueous solution BaCl₂ behaves as a simple salt; in water it is a 1:2 electrolyte and the solution exhibits a neutral pH. Its solutions react with sulfate ion to produce a thick white precipitate of barium sulfate.

Ba²⁺ + SO₄²⁻ → BaSO₄

Oxalate effects a similar reaction:

Ba²⁺ + C₂O₄²⁻ → BaC₂O₄

When it is mixed with sodium hydroxide, it gives the dihydroxide, which is moderately soluble in water.

Preparation

On an industrial scale, it is prepared via a two step process from barite (barium sulfate):[10]

BaSO₄ + 4 C → BaS + 4 CO

This first step requires high temperatures.

BaS + 2 HCl → BaCl₂ + H₂S

In place of HCl, chlorine can be used.[5]

Barium chloride can in principle be prepared from barium hydroxide or barium carbonate. These basic salts react with hydrochloric acid to give hydrated barium chloride.

Uses

Although inexpensive, barium chloride finds limited applications in the laboratory and industry. 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.[5] Its toxicity limits its applicability.

Safety

Barium chloride, along with other water-soluble barium salts, is highly toxic.[11] Sodium sulfate and magnesium sulfate are potential antidotes because they form barium sulfate BaSO₄, which is relatively non-toxic because of its insolubility.

References

Chemical Recreations: A Series of Amusing and Instructive Experiments, which May be Performed with Ease, Safety, Success, and Economy ; to which is Added, the Romance of Chemistry : An Inquiry into the Fallacies of the Prevailing Theory of Chemistry : With a New Theory and a New Nomenclature. R. Griffin & Company. 1834.
Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
"Barium (soluble compounds, as Ba)". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
NIOSH Pocket Guide to Chemical Hazards. "#0045". National Institute for Occupational Safety and Health (NIOSH).
Kresse, Robert; Baudis, Ulrich; Jäger, Paul; Riechers, H. Hermann; Wagner, Heinz; Winkler, Jocher; Wolf, Hans Uwe (2007). "Barium and Barium Compounds". In Ullman, Franz (ed.). Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.a03_325.pub2. ISBN 978-3527306732.
Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
Haase, A.; Brauer, G. (1978). "Hydratstufen und Kristallstrukturen von Bariumchlorid". Z. anorg. allg. Chem. 441: 181–195. doi:10.1002/zaac.19784410120.
Brackett, E. B.; Brackett, T. E.; Sass, R. L. (1963). "The Crystal Structures of Barium Chloride, Barium Bromide, and Barium Iodide". J. Phys. Chem. 67 (10): 2132. doi:10.1021/j100804a038.
Léger, J. M.; Haines, J.; Atouf, A. (1995). "The Post-Cotunnite Phase in BaCl₂, BaBr₂ and BaI₂ under High Pressure". J. Appl. Cryst. 28 (4): 416. doi:10.1107/S0021889895001580.
Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
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)
Barium chloride's use in industry.
ChemSub Online: Barium chloride.

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[1] Chemical Recreations: A Series of Amusing and Instructive Experiments, which May be Performed with Ease, Safety, Success, and Economy ; to which is Added, the Romance of Chemistry : An Inquiry into the Fallacies of the Prevailing Theory of Chemistry : With a New Theory and a New Nomenclature. R. Griffin & Company. 1834.

[2] Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.

[IDLH-3] "Barium (soluble compounds, as Ba)". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[PGCH-4] NIOSH Pocket Guide to Chemical Hazards. "#0045". National Institute for Occupational Safety and Health (NIOSH).

[Ullman2005-5] Kresse, Robert; Baudis, Ulrich; Jäger, Paul; Riechers, H. Hermann; Wagner, Heinz; Winkler, Jocher; Wolf, Hans Uwe (2007). "Barium and Barium Compounds". In Ullman, Franz (ed.). Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.a03_325.pub2. ISBN 978-3527306732.

[6] Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.

[7] Haase, A.; Brauer, G. (1978). "Hydratstufen und Kristallstrukturen von Bariumchlorid". Z. anorg. allg. Chem. 441: 181–195. doi:10.1002/zaac.19784410120.

[8] Brackett, E. B.; Brackett, T. E.; Sass, R. L. (1963). "The Crystal Structures of Barium Chloride, Barium Bromide, and Barium Iodide". J. Phys. Chem. 67 (10): 2132. doi:10.1021/j100804a038.

[9] Léger, J. M.; Haines, J.; Atouf, A. (1995). "The Post-Cotunnite Phase in BaCl₂, BaBr₂ and BaI₂ under High Pressure". J. Appl. Cryst. 28 (4): 416. doi:10.1107/S0021889895001580.

[10] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

[11] The Merck Index, 7th edition, Merck & Co., Rahway, New Jersey, 1960.