View source for Calcium chloride

{{Chembox new
| Name = Calcium chloride
| ImageFile = Calcium chloride.jpg
| ImageSize = 200px
| ImageName = Calcium chloride
| IUPACName = calcium chloride
| OtherNames = calcium(II) chloride,<br />calcium dichloride,<br />E509
| Section1 = {{Chembox Identifiers
| CASNo = 10043-52-4
| RTECS = EV9800000, [[Anhydrous]]
 }}
| Section2 = {{Chembox Properties
| Formula = CaCl<sub>2</sub><br />CaCl<sub>2</sub>.2H<sub>2</sub>O [[Dihydrate]]<br />CaCl<sub>2</sub>.4H<sub>2</sub>O [[Tetrahydrate]]<br />CaCl<sub>2</sub>.6H<sub>2</sub>O [[Hexahydrate]]
| MolarMass = 110.99 g/mol, anhydrous<br />147.02 g/mol, dihydrate<br />183.04 g/mol, tetrahydrate<br />219.08 g/mol, hexahydrate
| Appearance = white or colorless solid
| Density = 2.15 g/cm³, anhydrous<br />0.835 g/cm³, dihydrate<br /> 1.71 g/cm³, hexahydrate
| Solubility = 74.5 g/100&nbsp;ml (20&nbsp;°C)
| MeltingPt = 772&nbsp;°C (anhydrous)
| BoilingPt = >1600 °C
 }}
| Section3 = {{Chembox Structure
| Coordination = [[octahedral]], 6-coordinate
| CrystalStruct = deformed [[rutile]]
 }}
| Section7 = {{Chembox Hazards
| EUClass = Irritant ('''Xi''')
| NFPA-H = 1
| NFPA-F =
| NFPA-R =
| RPhrases = {{R36}}
| SPhrases = {{S2}}, {{S22}}, {{S24}}
 }}
| Section8 = {{Chembox Related
| OtherAnions = [[calcium fluoride]]<br />[[calcium bromide]]<br />[[calcium iodide]]
| OtherCations = [[magnesium chloride]]<br />[[strontium chloride]]
 }}
}}
'''Calcium chloride''' (CaCl<sub>2</sub>), is an [[ion|ionic compound]] of [[calcium]] and [[chlorine]]. It is highly [[soluble]] in water and it is [[deliquescent]]. It is a [[Salt (chemistry)|salt]] that is [[solid]] at [[room temperature]], and it behaves as a typical [[ion]]ic [[halide]]. It has several common applications such as [[brine]] for refrigeration plants, [[ice]] and dust control on roads, and in [[cement]]. It can be produced directly from [[limestone]], but large amounts are also produced as a by-product of the [[Solvay process]]. Because of its [[hygroscopic]] nature, it must be kept in tightly-sealed containers.

==Chemical properties==
Calcium Chloride can serve as a source of calcium [[ions]] in [[solution]], for instance for [[Precipitation (chemistry)|precipitation]] because many calcium [[Chemical compound|compounds]] are [[insoluble]]:

3 CaCl<sub>2</sub>([[Aqueous solution|aq]]) + 2 [[potassium phosphate|K<sub>3</sub>PO<sub>4</sub>]]([[Aqueous solution|aq]]) → [[calcium phosphate|Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>]]([[solid|s]]) + 6 [[potassium chloride|KCl]]([[Aqueous solution|aq]])

Molten CaCl<sub>2</sub> can be [[electrolysis|electrolysed]] to give [[calcium]] metal:<br />

CaCl<sub>2</sub>([[liquid|l]]) → Ca([[solid|s]]) + Cl<sub>2</sub>([[gas|g]])



==Uses (industrial) ==
Millions of [[tonne]]s of calcium chloride are made each year in the US alone, and it has a wide variety of industrial applications:

Because it is strongly [[hygroscopic]], [[air]] or other [[gas]]es may be channeled through a column of calcium chloride to remove moisture. In particular, calcium chloride is usually used to pack [[drying tube]]s to exclude atmospheric moisture from a reaction set-up while allowing gases to escape. It can also be added to liquids to remove suspended or dissolved water. The dissolving process is highly [[exothermic]] and rapidly produces temperatures of around 60 °[[Celsius|C]] (140 °[[Fahrenheit|F]]). In this capacity, it is known as a drying agent or [[desiccant]]. It is converted to a [[brine]] as it absorbs the [[water]] or [[water vapor]] from the substance to be dried:

:CaCl<Sub>2</sub> + 2 H<Sub>2</sub>O → CaCl<Sub>2</sub>·2H<Sub>2</sub>O

Aided by the intense heat evolved during its dissolution, calcium chloride is also used as an [[ice]]-melting compound. Unlike the more-common [[sodium chloride]] (rock salt or [[halite]]), it is relatively harmless to plants and soil; however, recent observations in Washington state suggest it may be particularly harsh on roadside evergreen trees.<ref>{{cite web
 | title = De-icer damaging thousands of trees on mountain passes
 | publisher = The Seattle Times
 | date = [[19 March]] [[2008]]
 | url = http://seattletimes.nwsource.com/html/localnews/2004291523_treekill19m.html
 | accessmonthday = 18 March | accessyear=2008}}</ref> 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 millimetres in diameter, called [[prills]] (see picture at top of page).

Used for its [[hygroscopic]] property, it can be applied to keep a liquid layer on the surface of the roadway, which holds dust down.<ref>{{cite web
 | title = Dust: Don't Eat It! Control It!
 | work = Road Management & Engineering Journal
 | publisher = US Roads (TranSafety Inc.)
 | date = [[1 June]] [[1998]]
 | url = http://www.usroads.com/journals/rmej/9806/rm980603.htm
 | accessmonthday = 9 August | accessyear=2006}}</ref> It is used in concrete mixes to help speed up the initial setting, however chloride ion leads to corrosion of steel [[rebar]], so it should not be used in [[reinforced concrete]].<ref>{{cite web
 | title = Accelerating Concrete Set Time
 | publisherUS [[Federal Highway Administration]]
 | date = [[1 June]] [[1999]]
 | url = http://www.fhwa.dot.gov/infrastructure/materialsgrp/acclerat.htm
 | accessmonthday = January 16 | accessyear=2007}}</ref>

Aqueous calcium chloride (in solution with water) lowers the freezing point as low as -52°C (-62°F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.<ref>{{cite web
 | title = Agricultural Tire Hydroinflation
 | work = www.firestoneag.com
 | publisher = Firestone Tires
 | date = December 2007
 | url = http://www.firestoneag.com/tiredata/info/info_hydro_2.asp
 | accessmonthday = 3 December | accessyear=2007}}</ref>

Other industrial applications include use as as an additive in plastics, as a drainage aid for wastewater treatment, as an additive in [[fire extinguisher]]s, as an additive in control scaffolding in [[blast furnace]]s, and as a thinner in [[fabric softener]].

== Uses (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. The anhydrous form has been approved by the FDA as a packaging aid to ensure dryness (CPG 7117.02).<ref>{{cite web
 | title = CPG 7117.02
 | work = FDA Compliance Articles
 | publisher = US Food and Drug Administration
 | date = March 1995
 | url = http://www.fda.gov/ora/compliance_ref/cpg/cpgfod/cpg500-400.html
 | accessmonthday = 3 December | accessyear=2007}}</ref>

Calcium chloride is commonly used as an [[Electrolyte]] and has an extremely [[salty]] taste, as found in sports drinks and other beverages such as [[Glacéau|Smartwater]] and [[Nestle]] bottled water. It can also be used as a preservative to maintain firmness in canned vegetables or in higher concentrations in [[Pickled cucumber|pickles]] to give a salty taste while not increasing the food's [[sodium]] content. It is even found in snack foods, including [[Cadbury Caramilk]] chocolate bars (purpose unknown).

It can be used to make a [[caviar]] substitute from vegetable or fruit juices<ref>{{cite web
 | title = Apple Caviar Technique
 | work = StarChefs Studio
 | publisher = StarChefs.com
 | date = April 2004
 | url = http://www.starchefs.com/events/studio/techniques/FAdria/index.shtml
 | accessmonthday = 9 August | accessyear=2006}}</ref> or added to processed milk to restore the natural balance between calcium and protein for the purposes of making cheese such as [[brie (cheese)|brie]] and [[stilton (cheese)|stilton]]. Calcium chloride's exothermic properties are exploited in many 'self heating' food products where it is activated (mixed) with water to start the heating process, providing a non-explosive, dry fuel that is easily activated.

In brewing beers (esp. ales and bitters), calcium chloride is sometimes used to correct mineral deficiencies in the brewing water (calcium is important for enzyme function during the mash, for kettle protein coagulation (the "hot break") and yeast metabolism) and adds permanent hardness to the water. The chloride ions enhance flavour and give a perception of sweetness and fuller flavour, whereas the sulfate ions in [[Gypsum]], which is also used to add calcium ions to brewing water, tend to impart a drier, crisper flavour with more bitterness.

== Uses (biological/medical) ==
Calcium chloride can be injected as [[intravenous therapy]] for the treatment of [[hypocalcaemia]] (low serum calcium). It can be used for: insect bites or stings (such as Black Widow Spider bites); sensitivity reactions, particularly when characterized by [[urticaria]] (hives); magnesium intoxication; as an aid in management of the acute symptoms in lead colic; in cardiac resuscitation, particularly after open heart surgery. [[Parenteral]] calcium can be used when [[epinephrine]] has failed to improve weak or ineffective [[myocardial]] contractions. Calcium chloride injection may antagonize cardiac toxicity as measured by [[electrocardiogram]] (ECG/EKG).[http://www.rxmed.com/b.main/b2.pharmaceutical/b2.1.monographs/CPS-%20Monographs/CPS-%20(General%20Monographs-%20C)/CALCIUM%20CHLORIDE%20INJECTION%20USP.html] 

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 Diltiazem ([[Cardizem]])—helping avoid potential heart attacks.

The aqueous form of calcium chloride is used in genetic [[Transformation (genetics)|transformation]] of cells by increasing the cell membrane permeability, inducing [[competence (biology)|competence]] for DNA uptake (allowing DNA fragments to enter the cell more readily).

It can also be used in the [[reef aquarium]] hobby for adding bio-available calcium in solution for calcium-using animals such as [[algae]], [[snails]], hard [[tube worm]]s, and [[Corals]] although the use of [[calcium hydroxide]] (kalkwasser mix) or a [[calcium reactor]] is the preferred method of adding calcium.  However, calcium chloride is the quickest method to increase calcium levels as it dissolves readily in water.

==Precautions==
Calcium chloride is an irritant, particularly on moist skin. Wear gloves and goggles or a full face shield to protect hands and eyes; avoid inhalation.

Dry calcium chloride reacts [[exothermic reaction|exothermically]] when exposed to water. [[Burn (injury)|Burns]] can result in the mouth and [[esophagus]] if humans or other animals ingest dry calcium chloride pellets. Small children are more susceptible than adults (who generally have had experience trying to eat hot food, and can react accordingly) so calcium chloride pellets should be kept out of their reach.

==References==
<references/>
==General references==
* {{Greenwood&Earnshaw}}
* ''Handbook of Chemistry and Physics'', 71st edition, CRC Press, Ann Arbor, Michigan, 1990.

==External links==
* [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc11/icsc1184.htm International Chemical Safety Card 1184]
* [http://www.dow.com/webapps/lit/litorder.asp?filepath=calcium/pdfs/noreg/173-01534.pdf&pdf=true Calcium Chloride Handbook from Dow Chemical (pdf 1.6&nbsp;MB)]
* [http://wwwprod.dot.state.fl.us/research-center/Completed_Proj/Summary_SMO/FDOT_806_rpt.pdf Report on steel corrosion by chloride including CaCl<sub>2</sub>]
* [http://glchloride.com/links.php Collection of Calcium Chloride Reports and Articles]

{{Mineral supplements}}
{{Urologicals}}

[[Category:Calcium compounds]]
[[Category:Chlorides]]
[[Category:Metal halides]]
[[Category:Deliquescent substances]]
[[Category:Desiccants]]
[[Category:Pyrotechnic colons]]

[[ar:كلوريد كالسيوم]]
[[ca:Clorur de calci]]
[[da:Kalciumklorid]]
[[de:Calciumchlorid]]
[[es:Cloruro de calcio]]
[[fr:Chlorure de calcium]]
[[gl:Cloruro de calcio]]
[[it:Cloruro di calcio]]
[[lv:Kalcija hlorīds]]
[[hu:Kalcium-klorid]]
[[nl:Calciumchloride]]
[[ja:塩化カルシウム]]
[[nn:Kalsiumklorid]]
[[pl:Chlorek wapnia]]
[[pt:Cloreto de cálcio]]
[[ru:Хлорид кальция]]
[[sr:Калцијум хлорид]]
[[fi:Kalsiumkloridi]]
[[sv:Kalciumklorid]]
[[vi:Canxi clorua]]
[[zh:氯化鈣]]