Calcium chloride

Calcium chloride
IUPAC name Calcium chloride
Other names Calcium(II) chloride, Calcium dichloride, E509
Identifiers
CAS number	10043-52-4 Y,  22691-02-7 (monohydrate) 10035-04-8 (dihydrate) 25094-02-4 (tetrahydrate) 7774-34-7 (hexahydrate)
PubChem	24854
ChemSpider	23237 Y
UNII	OFM21057LP Y
EC number	233-140-8
DrugBank	DB01164
ChEBI	CHEBI:3312 Y
ChEMBL	CHEMBL1200668 N
RTECS number	EV9800000
Jmol-3D images	Image 1
SMILES [Ca+2].[Cl-].[Cl-]
InChI InChI=1S/Ca.2ClH/h;2*1H/q+2;;/p-2 Y Key: UXVMQQNJUSDDNG-UHFFFAOYSA-L Y InChI=1/Ca.2ClH/h;2*1H/q+2;;/p-2 Key: UXVMQQNJUSDDNG-NUQVWONBAG
Properties
Molecular formula	CaCl2
Molar mass	110.98 g/mol (anhydrous) 128.999 g/mol (monohydrate) 147.014 g/mol (dihydrate) 183.045 g/mol (tetrahydrate) 219.08 g/mol (hexahydrate)
Appearance	white solid
Density	2.15 g/cm3 (anhydrous) 1.835 g/cm3 (dihydrate) 1.83 g/cm3 (tetrahydrate) 1.71 g/cm3 (hexahydrate)
Melting point	772 °C (anhydrous) 260 °C (monohydrate) 176 °C (dihydrate) 45.5 °C (tetrahydrate) 30 °C (hexahydrate) [1]
Boiling point	1935 °C (anhydrous)
Solubility in water	74.5 g/100mL (20 °C) 59.5 g/100 mL (0 °C)
Solubility in alcohol	soluble
Acidity (pKa)	8-9 (anhydrous) 6.5-8.0 (hexahydrate)
Structure
Crystal structure	Orthorhombic (deformed rutile), oP6
Space group	Pnnm, No. 58
Coordination geometry	octahedral, 6-coordinate
Hazards
MSDS	External MSDS
EU Index	017-013-00-2
EU classification	Irritant (Xi)
R-phrases	R36
S-phrases	(S2), S22, S24
NFPA 704	0 2 1
LD50	1000 mg/kg (oral, rat)
Related compounds
Other anions	calcium fluoride calcium bromide calcium iodide
Other cations	Beryllium chloride Magnesium chloride Strontium chloride Barium chloride Radium chloride
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
N chloride (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Calcium chloride, CaCl₂, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation. Because of its hygroscopic nature, anhydrous calcium chloride must be kept in tightly-sealed air-tight containers.

Properties

Calcium chloride can serve as a source of calcium ions in a solution as calcium chloride is soluble. This property can be useful for displacing ions from solution. For example, phosphate is displaced from solution by calcium:

3 CaCl₂ (aq) + 2 K₃PO₄ (aq) → Ca₃(PO₄)₂ (s) + 6 KCl (aq)

Molten calcium chloride can be electrolysed to give calcium metal and chlorine gas:

CaCl₂ (l) → Ca (s) + Cl₂ (g)

Calcium chloride has a very high enthalpy change of solution.

The anhydrous salt is deliquescent; it can accumulate enough water in its crystal lattice to form a solution.

Preparation

Calcium chloride can be produced directly from limestone, but large amounts are also produced as a by-product of the Solvay process. North American consumption in 2002 was 1,687,000 tons (3.7 billion pounds).^[2] A Dow Chemical Company manufacturing facility in Michigan, houses about 35% of the total U.S. production capacity for calcium chloride.^[3]

Occurrence

Calcium chloride occurs as the rare evaporite minerals sinjarite (dihydrate) and antarcticite (hexahydrate). A related mineral chlorocalcite (potassium calcium chloride, KCaCl₃) is also very rare.

Uses

Desiccant

Drying tubes are frequently packed with calcium chloride. Kelp is dried with calcium chloride for use producing sodium carbonate. Adding solid calcium chloride to liquids can remove dissolved water. Calcium chloride is also used in products such as DampRid and Dri-Z-Air which is advertised as an air moisture absorber. Anhydrous calcium chloride has been approved by the FDA as a packaging aid to ensure dryness (CPG 7117.02).^[4]

These hygroscopic properties are also applied to keep a liquid layer on the surface of the roadway, which holds dust down.^[5]

Deicing and freezing point depression

By depressing the freezing-point calcium chloride is used to prevent ice formation and to deice. This is particularly useful on road surfaces. Calcium chloride dissolution is exothermic, and is relatively harmless to plants and soil; however, recent observations in Washington state suggest it may be particularly harsh on roadside evergreen trees.^[6] It is also more effective at lower temperatures than sodium chloride. When distributed for this use, it usually takes the form of small white balls a few millimeters in diameter, called prills. Solutions of calcium chloride can prevent freezing at temperature as low as −52 °C (−62 °F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.^[7]

Source of calcium ions

Calcium chloride is used to increase the hardness in swimming pools. This reduces the erosion of the concrete in the pool. By Le Chatelier's principle and the common ion effect, increasing the concentration of calcium in the water will reduce the dissolution of calcium compounds essential to the structure of concrete.^{[citation needed]}

In marine aquariums calcium chloride is added to introduce bioavailable calcium for calcium carbonate shelled animals such as mollusks and cnidarians. Calcium hydroxide (kalkwasser mix) or a calcium reactor can also be used to introduce calcium, however calcium chloride addition is the fastest method and has minimal impact on pH.

Food

As an ingredient, it is listed as a permitted food additive in the European Union for use as a sequestrant and firming agent with the E number E509, and considered as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration.^[8] The average intake of calcium chloride as food additives has been estimated to be 160–345 mg/day for individuals.^[9]

As a firming agent calcium chloride is used in canned vegetables, in firming soy bean curds into tofu and in producing a caviar substitute from vegetable or fruit juices.^[10] It is commonly used as an electrolyte in sports drinks and other beverages including Smartwater and Nestle bottled water. The extremely salty taste of calcium chloride is used to flavor pickles while not increasing the food's sodium content. Calcium chloride's freezing-point depression properties are used, for example, in Cadbury Caramilk chocolate bars to slow the freezing of the caramel.

In brewing beer, calcium chloride is sometimes used to correct mineral deficiencies in the brewing water. It affects flavor and chemical reactions during the brewing process, and can also affect yeast function during fermentation. Calcium chloride is sometimes added to processed milk to restore the natural balance between calcium and protein in casein for the purposes of making cheese such as brie, Pélardon and stilton.

Medicine

Calcium chloride can be injected as intravenous therapy for the treatment of hypocalcaemia. It can be used for magnesium intoxication. Calcium chloride injection may antagonize cardiac toxicity as measured by electrocardiogram. It can help to protect the myocardium from dangerously high levels of serum potassium in hyperkalemia. Calcium chloride can be used to quickly treat Calcium Channel Blocker toxicity, from the side effects of drugs such as Cardizem — helping avoid potential heart attacks. ^[11]

Aqueous calcium chloride is used in genetic transformation of cells by increasing the cell membrane permeability, inducing competence for DNA uptake (allowing DNA fragments to enter the cell more readily).

Other

Calcium chloride is used in concrete mixes to help speed up the initial setting, but chloride ion leads to corrosion of steel rebar, so it should not be used in reinforced concrete.^[12] The anhydrous form of calcium chloride may also be used for this purpose and can provide a measure of the moisture in concrete.^[13]

Calcium chloride is used in swimming pool water as a pH buffer and to adjust the calcium hardness of the water.

Calcium chloride is included as an additive in plastics and in fire extinguishers, in wastewater treatment as a drainage aid, in blast furnaces as an additive to control scaffolding (clumping and adhesion of materials that prevent the furnace charge from descending), and in fabric softener as a thinner.

The exothermic dissolution of calcium chloride is used in self-heating cans and heating pads.

In the oil industry calcium chloride is used to increase the density of solids free brines. It is also used to provide inhibition of swelling clays in the water phase of invert emulsion drilling fluids.

Toxicology

Calcium chloride can act as an irritant by desiccating moist skin. Solid calcium chloride dissolves exothermically and burns can result in the mouth and esophagus if calcium chloride is ingested. Ingestion of concentrated solutions or solid calcium chloride products may cause gastrointestinal irritation or ulceration.^[14]

See also

• Calcium(I) chloride
• Calcium chloride transformation

References

1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
2. ^ Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, October 22–25, 2002, page 11.
3. ^ Calcium Chloride Chemical Profile, The Innovation Group, www.the-innovation-group.com, printed September 9, 2005.
4. ^ "CPG 7117.02". FDA Compliance Articles. US Food and Drug Administration. March 1995. http://www.fda.gov/ora/compliance_ref/cpg/cpgfod/cpg500-400.html. Retrieved 3 December 2007. 
5. ^ "Dust: Don't Eat It! Control It!". Road Management & Engineering Journal. US Roads (TranSafety Inc.). 1 June 1998. http://www.usroads.com/journals/rmej/9806/rm980603.htm. Retrieved 9 August 2006. 
6. ^ "De-icer damaging thousands of trees on mountain passes". The Seattle Times. 19 March 2008. http://seattletimes.nwsource.com/html/localnews/2004291523_treekill19m.html. Retrieved 18 March 2008. 
7. ^ "Agricultural Tire Hydroinflation". www.firestoneag.com. Firestone Tires. December 2007. http://www.firestoneag.com/tiredata/info/info_hydro_2.asp. Retrieved 3 December 2007. 
8. ^ 21 CFR § 184.1193
9. ^ Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, October 22–25, 2002, pages 13-14.
10. ^ "Apple Caviar Technique". StarChefs Studio. StarChefs.com. April 2004. http://www.starchefs.com/events/studio/techniques/FAdria/index.shtml. Retrieved 9 August 2006. 
11. ^ "Calcium chloride Prescribing Information". Hospira, Inc.. November 2009. http://www.drugs.com/pro/calcium-chloride.html. Retrieved 10 June 2011. 
12. ^ "Accelerating Concrete Set Time". Federal Highway Administration. 1 June 1999. http://www.fhwa.dot.gov/infrastructure/materialsgrp/acclerat.htm. Retrieved January 16, 2007. 
13. ^ National Research Council (U.S.). Building Research Institute (1962). Adhesives in Building: Selection and Field Application; Pressure-sensitive Tapes. National Academy of Science-National Research Council. pp. 24–5. 
14. ^ "Product Safety Assessment (PSA): Calcium Chloride". Dow Chemical Company. May 2, 2006. http://www.dow.com/productsafety/finder/cacl_2.htm. 

• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
• Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.

External links

• International Chemical Safety Card 1184
• Product and Application Information (Formerly Dow Chemical Calcium Chloride division)
• Report on steel corrosion by chloride including CaCl₂
• Collection of calcium chloride reports and articles
• MSDS sheet for Calcium Chloride

Template:Calcium compound