View source for Calcium chloride

{{short description|Chemical compound}}
{{cs1 config|name-list-style=vanc}}
{{Use dmy dates|date=March 2021}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 477163394
| Name = Calcium chloride
| ImageFile = File:Kristallstruktur Calciumchlorid.png
| ImageSize = 160px
| ImageName = Structure of calcium chloride, (chlorine is green, calcium is gray)
| ImageFile1 = Calcium chloride CaCl2.jpg
| ImageName1 = Sample of calcium chloride
| IUPACName = Calcium chloride
| OtherNames = {{unbulleted list|Neutral calcium chloride|calcium(II) chloride|calcium dichloride (1:2)|E509}}
|Section1={{Chembox Identifiers
| ChemSpiderID = 23237
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII = OFM21057LP
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = LEV48803S9
| UNII1_Comment = (monohydrate)
| UNII2_Ref = {{fdacite|correct|FDA}}
| UNII2 = M4I0D6VV5M
| UNII2_Comment = (dihydrate)
| UNII4_Ref = {{fdacite|correct|FDA}}
| UNII4 = 1D898P42YW
| UNII4_Comment = (hexahydrate)
| ChEMBL = 1200668
| ChEMBL_Ref = {{ebicite|changed|??}}
| ChEBI = 3312
| ChEBI_Ref = {{ebicite|correct|??}}
| DrugBank = DB01164
| DrugBank_Ref = {{drugbankcite|correct|??}}
| SMILES = Cl[Ca]Cl
| SMILES2 = [Ca+2].[Cl-].[Cl-]
| SMILES3 = Cl[Ca]Cl.O
| SMILES3_Comment = monohydrate
| SMILES4 = Cl[Ca]Cl.O.O
| SMILES4_Comment = dihydrate
| SMILES5 = Cl[Ca]Cl.O.O.O.O.O.O
| SMILES5_Comment = hexahydrate
| InChI = 1/Ca.2ClH/h;2*1H/q+2;;/p-2
| InChIKey = UXVMQQNJUSDDNG-NUQVWONBAG
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/Ca.2ClH/h;2*1H/q+2;;/p-2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = UXVMQQNJUSDDNG-UHFFFAOYSA-L
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 10043-52-4
| CASNo_Comment = 
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1 = 22691-02-7
| CASNo1_Comment = (monohydrate)
| CASNo2_Ref = {{cascite|correct|CAS}}
| CASNo2 = 10035-04-8
| CASNo2_Comment = (dihydrate)
| CASNo3_Ref = {{cascite|changed|??}}
| CASNo3 = 25094-02-4
| CASNo3_Comment = (tetrahydrate)
| CASNo4_Ref = {{cascite|correct|CAS}}
| CASNo4 = 7774-34-7
| CASNo4_Comment = (hexahydrate)
| PubChem = 24854
| RTECS = EV9800000
| EC_number = 233-140-8
}}
|Section2={{Chembox Properties
| Ca=1|Cl=2
| Appearance = White [[hygroscopic]] powder
| Odor = Odorless
| Density = {{ubl
 | 2.15 g/cm<sup>3</sup> (anhydrous)
 | 2.24 g/cm<sup>3</sup> (monohydrate)
 | 1.85 g/cm<sup>3</sup> (dihydrate)
 | 1.83 g/cm<sup>3</sup> (tetrahydrate)
 | 1.71 g/cm<sup>3</sup> (hexahydrate)<ref name=crc>{{CRC90}}</ref>
}}
| MeltingPtC = 772–775
| MeltingPt_notes = <br> anhydrous<ref name=pphoic /><br><!--
 -->{{convert|260|C|F K}}<br> monohydrate, decomposes<br><!--
 -->{{convert|175|C|F K}}<br> dihydrate, decomposes<br><!--
 -->{{convert|45.5|C|F K}}<br> tetrahydrate, decomposes<ref name=pphoic>{{cite book |last=Pradyot |first=Patnaik |title=Handbook of Inorganic Chemicals |publisher=The McGraw-Hill Companies, Inc. |year=2019 |page=162 |isbn=978-0-07-049439-8}}</ref><br><!--
 -->{{convert|30|C|F K}}<br> hexahydrate, decomposes<ref name=crc />
| BoilingPtC = 1935
| BoilingPt_notes = anhydrous<ref name=crc />
| Solubility = Anhydrous: <br><!--
  -->74.5 g/100 mL (20&nbsp;°C)<ref name=ISCS>{{cite web |title=Calcium chloride (anhydrous) |url=http://www.inchem.org/documents/icsc/icsc/eics1184.htm |url-status=live |website=ICSC |publisher=International Programme on Chemical Safety and the European Commission |access-date=18 September 2015 |archive-url=https://web.archive.org/web/20150925091632/http://www.inchem.org/documents/icsc/icsc/eics1184.htm |archive-date=25 September 2015}}</ref><br><!--
 -->Hexahydrate:<br><!--
  -->49.4 g/100 mL (−25&nbsp;°C)<br><!--
  -->59.5 g/100 mL (0&nbsp;°C)<br><!--
  -->65 g/100 mL (10&nbsp;°C)<br><!--
  -->81.1 g/100 mL (25&nbsp;°C)<ref name=crc /><br><!--
  -->102.2 g/100 mL (30.2&nbsp;°C)<br><!--
 -->α-Tetrahydrate:<br><!--
  -->90.8 g/100 mL (20&nbsp;°C)<br><!--
  -->114.4 g/100 mL (40&nbsp;°C)<br><!--
 -->Dihydrate:<br><!--
  -->134.5 g/100 mL (60&nbsp;°C)<br><!--
  -->152.4 g/100 mL (100&nbsp;°C)<ref name=sioc>{{cite book |last1=Seidell |first1=Atherton |last2=Linke |first2=William F. |title=Solubilities of Inorganic and Organic Compounds |url=https://archive.org/details/solubilitiesino01seidgoog |publisher=D. Van Nostrand Company |location=New York |edition=second |year=1919 |page=[https://archive.org/details/solubilitiesino01seidgoog/page/n224 196]}}</ref>
| SolubleOther = {{ubl
 | Soluble in [[acetic acid]], [[Alcohol (chemistry)|alcohol]]s
 | Insoluble in liquid [[ammonia]], [[dimethyl sulfoxide]] (DMSO), [[ethyl acetate]]<ref name=chemister />
 }}
| Solubility1 = {{ubl
 | 18.3 g/100 g (0&nbsp;°C)
 | 25.8 g/100 g (20&nbsp;°C)
 | 35.3 g/100 g (40&nbsp;°C)
 | 56.2 g/100 g (70&nbsp;°C)<ref name=chemister>{{cite web |last=Anatolievich |first=Kiper Ruslan |title=Properties of substance: calcium chloride |url=http://chemister.ru/Database/properties-en.php?dbid=1&id=558 |work=chemister.ru |access-date=7 July 2014 |archive-url=https://web.archive.org/web/20150624025121/http://chemister.ru/Database/properties-en.php?dbid=1&id=558 |archive-date=24 June 2015 |url-status=live}}</ref>
}}
| Solvent1 = ethanol
| Solubility2 = {{ubl
 | 21.8 g/100 g (0&nbsp;°C)
 | 29.2 g/100 g (20&nbsp;°C)
 | 38.5 g/100 g (40&nbsp;°C)<ref name=chemister />
}}
| Solvent2 = methanol
| Solubility3 = 0.1 g/kg (20&nbsp;°C)<ref name=chemister />
| Solvent3 = acetone
| Solubility4 = 16.6 g/kg<ref name=chemister />
| Solvent4 = pyridine
| Viscosity = {{ubl
 | 3.34 cP (787&nbsp;°C)
 | 1.44 cP (967&nbsp;°C)<ref name=chemister />
}}
| MagSus = −5.47·10<sup>−5</sup>{{nbsp}}cm<sup>3</sup>/mol<ref name=crc />
| pKa = {{ubl
 | 8–9 (anhydrous)
 | 6.5–8.0 (hexahydrate)
}}
| RefractIndex = 1.52
}}
|Section3={{Chembox Structure
| Coordination = [[Octahedral]] at {{chem2|Ca(2+)}} centres (anhydrous)
| CrystalStruct = {{ubl
 | [[orthorhombic crystal system|Orthorhombic]] ([[rutile]], anhydrous), [[Pearson symbol|oP6]]
 | [[tetragonal crystal system|Tetragonal]] (anhydrous, > 217&nbsp;°C), [[Pearson symbol|oP6]]<ref name=isc>{{cite book |last=Müller |first=Ulrich |title=Inorganic Structural Chemistry |url=https://books.google.com/books?id=s3KlfXCY11sC&pg=PA33 |publisher=[[John Wiley & Sons Ltd.]] |location=England |edition=second |year=2006 |page=33 |isbn=978-0-470-01864-4}}</ref>
 | [[trigonal crystal system|Trigonal]] (hexahydrate)
}}
| SpaceGroup = {{ubl
 | Pnnm, No. 58 (anhydrous)
 | P4<sub>2</sub>/mnm, No. 136 (anhydrous, >217&nbsp;°C)<ref name=isc />
}}
| PointGroup = {{ubl
 | 2/m 2/m 2/m (anhydrous)
 | 4/m 2/m 2/m (anhydrous, >217&nbsp;°C)<ref name=isc />
}}
| LattConst_a = 6.259&nbsp;Å
| LattConst_b = 6.444&nbsp;Å
| LattConst_c = 4.17&nbsp;Å (anhydrous, 17&nbsp;°C)<ref name=isc />
| LattConst_alpha = 90
}}
|Section5={{Chembox Thermochemistry
| HeatCapacity = {{ubl
 | 72.89 J/(mol·K) (anhydrous)<ref name=crc />
 | 106.23 J/(mol·K) (monohydrate)
 | 172.92 J/(mol·K) (dihydrate)
 | 251.17 J/(mol·K) (tetrahydrate)
 | 300.7 J/(mol·K) (hexahydrate)<ref name=pphoic />
}}
| Entropy = 108.4 J/(mol·K)<ref name=crc /><ref name=pphoic />
| DeltaHf = {{ubl
 | −795.42 kJ/mol (anhydrous)<ref name=crc />
 | −1110.98 kJ/mol (monohydrate)
 | −1403.98 kJ/mol (dihydrate)
 | −2009.99 kJ/mol (tetrahydrate)
 | −2608.01 kJ/mol (hexahydrate)<ref name=pphoic />
}}
| DeltaGf = −748.81 kJ/mol<ref name=crc /><ref name=pphoic />
| DeltaHc =
}}
|Section6={{Chembox Pharmacology
| ATCCode_prefix = A12
| ATCCode_suffix = AA07
| ATC_Supplemental = {{ATC|B05|XA07}}, {{ATC|G04|BA03}}
}}
|Section7={{Chembox Hazards
| MainHazards = Irritant
| GHSPictograms = {{GHS07}}<ref name="sigma">{{Sigma-Aldrich|id=499609|name=Calcium chloride|access-date=2014-07-07}}</ref>
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|319}}<ref name="sigma" />
| PPhrases = {{P-phrases|305+351+338}}<ref name="sigma" />
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 1
| NFPA_ref = <ref name=fca>{{cite web |title=MSDS of Calcium chloride |url=https://www.fishersci.ca/viewmsds.do?catNo=C6143 |url-status=live |work=fishersci.ca |publisher=Fisher Scientific |access-date=7 July 2014 |archive-url=https://web.archive.org/web/20150925114246/https://www.fishersci.ca/viewmsds.do?catNo=C6143 |archive-date=25 September 2015}}</ref>
| LD50 = 1,000-1,400 mg/kg (rats, oral)<ref name="natcc">{{cite book |last=Garrett |first=Donald E. |title=Handbook of Lithium and Natural Calcium Chloride |url=https://books.google.com/books?id=Ua2SVcUBHZgC&pg=PA379 |url-status=live |publisher=[[Elsevier]] |date=2004 |page=379 |quote=Its toxicity upon ingestion, is indicated by the test on rats: oral LD50 (rat) is 1.0–1.4 g/kg (the lethal dose for half of the test animals, in this case rats...) |access-date=29 August 2018 |archive-date=31 October 2023 |archive-url=https://web.archive.org/web/20231031190556/https://books.google.com/books?id=Ua2SVcUBHZgC&pg=PA379#v=onepage&q&f=false |isbn=978-0-08-047290-4}}</ref>
}}
|Section8={{Chembox Related
| OtherAnions = {{ubl
 | [[Calcium fluoride]]
 | [[Calcium bromide]]
 | [[Calcium iodide]]
}}
| OtherCations = {{ubl
 | [[Beryllium chloride]]
 | [[Magnesium chloride]]
 | [[Strontium chloride]]
 | [[Barium chloride]]
 | [[Radium chloride]]
}}
}}
}}

'''Calcium chloride''' is an [[inorganic compound]], a [[Salt (chemistry)|salt]] with the [[chemical formula]] {{chem2|CaCl2}}. It is a white crystalline solid at room temperature, and it is highly [[soluble]] in water. It can be created by neutralising [[hydrochloric acid]] with [[calcium hydroxide]].

Calcium chloride is commonly encountered as a [[Water of crystallization|hydrated]] solid with generic formula {{chem2|CaCl2*''n''H2O}}, where ''n'' = 0, 1, 2, 4, and 6. These compounds are mainly used for de-icing and dust control. Because the [[anhydrous]] salt is [[Hygroscopic|hygroscopic and deliquescent]], it is used as a [[desiccant]].<ref name=Ullmann>Robert Kemp, Suzanne E. Keegan "Calcium Chloride" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a04_547}}</ref>
{{TOC limit|3}}

== History ==
Calcium chloride was apparently discovered in the 15th century but wasn't studied properly until the 18th century.<ref>{{Cite book |last1=Peck |first1=Eugene L. |url=https://books.google.com/books?id=ZFZLAQAAMAAJ&q=+15th+century |title=Proceedings of the First Annual Heating and Air Conditioning Conference: 1953-1955 |last2=Hamilton |first2=J. Hugh |last3=Lewis |first3=John Roberts |last4=Hogan |first4=Mervin B. |last5=Kusian |first5=Ross Northey |last6=Cope |first6=William J. |date=1954 |publisher=University of Utah, Department of Metallurgy |access-date=4 February 2024 |archive-date=15 March 2024 |archive-url=https://web.archive.org/web/20240315015859/https://books.google.com/books?id=ZFZLAQAAMAAJ&q=+15th+century |url-status=live}}</ref> It was historically called "fixed [[Salammoniac|sal ammoniac]]" ({{langx|la|sal ammoniacum fixum}}<ref name=":0">{{cite book |last=Hartmann |first=Philipp Karl |url=https://books.google.com/books?id=Lx9VAAAAcAAJ&pg=PA299 |title=Pharmacologia Dynamica: Usui Academico Adcommodata |date=1816 |publisher=Kupffer et Wimmer |language=la |access-date=29 December 2023 |archive-date=29 December 2023 |archive-url=https://web.archive.org/web/20231229095150/https://books.google.com/books?id=Lx9VAAAAcAAJ&pg=PA299 |url-status=live}}</ref>) because it was synthesized during the distillation of [[ammonium chloride]] with lime and was nonvolatile (while the former appeared to [[Sublimation (phase transition)|sublime]]); in more modern times (18th-19th cc.) it was called "muriate of lime" ({{langx|la|murias calcis, calcaria muriatica}}<ref name=":0" />).<ref>{{cite book |last=Ottley |first=William Campbell |url=https://books.google.com/books?id=5LzUgQngwHgC&pg=PP374 |title=A dictionary of chemistry and of mineralogy as connected with it |date=1826 |publisher=Murray |access-date=29 December 2023 |archive-date=29 December 2023 |archive-url=https://web.archive.org/web/20231229095151/https://books.google.com/books?id=5LzUgQngwHgC&pg=PP374 |url-status=live}}</ref>

==Uses==

===De-icing and freezing-point depression===
{{Main article|De-icing}}
[[File:Cacl2 storage for winter road in japan.jpg|200px|thumbnail|left|Bulk {{chem2|CaCl2}} for de-icing in [[Japan]]]]
By [[freezing-point depression|depressing the freezing point]] of water, calcium chloride is used to prevent ice formation and is used to [[de-ice]]. This application consumes the greatest amount of calcium chloride. Calcium chloride is relatively harmless to plants and soil. As a de-icing agent, it is much more effective at lower temperatures than [[sodium chloride]]. When distributed for this use, it usually takes the form of small, white spheres a few millimeters in diameter, called [[prills]]. Solutions of calcium chloride can prevent freezing at temperatures as low as −52&nbsp;°C (−62&nbsp;°F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.<ref>{{cite web |title = Binary Phase diagram: The Calcium Chloride – water system |publisher = Aqueous Solutions Aps |date = October 2016 |url = http://www.phasediagram.dk/binary/calcium_chloride.htm |access-date = 20 April 2017 |archive-date = 26 June 2019 |archive-url = https://web.archive.org/web/20190626111339/http://www.phasediagram.dk/binary/calcium_chloride.htm |url-status = dead }}</ref>

It is also used in domestic and industrial chemical air [[dehumidifiers]].<ref>{{cite web |url= http://humantouchofchemistry.com/keeping-things-dry.htm |title= Keeping Things Dry |work=humantouchofchemistry.com |access-date= 2014-10-23 |archive-url= https://web.archive.org/web/20141026040358/http://humantouchofchemistry.com/keeping-things-dry.htm |archive-date= 26 October 2014 |url-status= dead }}</ref>

===Road surfacing===
{{Main articles|Road salt}}
[[File:Calcium chloride on a dirt road.jpg|thumb|left|Calcium chloride was sprayed on this road to prevent [[weathering]], giving it a wet appearance even in dry weather.]]
The second largest application of calcium chloride exploits its [[hygroscopic]] nature and the tackiness of its hydrates; calcium chloride is highly hygroscopic and its hydration is an [[exothermic process]]. A concentrated solution keeps a liquid layer on the surface of [[dirt road]]s, which suppresses the formation of dust. It keeps the finer dust particles on the road, providing a cushioning layer. If these are allowed to blow away, the large aggregate begins to shift around and the road breaks down. Using calcium chloride reduces the need for [[Grading (engineering)|grading]] by as much as 50% and the need for fill-in materials as much as 80%.<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 |access-date=9 August 2006 |archive-url=https://web.archive.org/web/20071029131300/http://www.usroads.com/journals/rmej/9806/rm980603.htm |archive-date=29 October 2007 |url-status=dead }}</ref>

===Food===
In the food industry, calcium chloride is frequently employed as a firming agent in canned vegetables, particularly for canned tomatoes and cucumber pickles.<ref name="q"/> It is also used in firming [[soybean]] curds into [[tofu]] and in producing a [[Spherification|caviar substitute from vegetable or fruit juices]].<ref name="q"/> It is also used to enhance the texture of various other products, such as whole apples, whole hot peppers, whole and sliced strawberries, diced tomatoes, and whole peaches.<ref name="p">{{cite journal |last1=Luna-Guzmán |first1=Irene |last2=Barrett |first2=Diane M |title=Comparison of calcium chloride and calcium lactate effectiveness in maintaining shelf stability and quality of fresh-cut cantaloupes |journal=Postharvest Biology and Technology |date=May 2000 |volume=19 |issue=1 |pages=61–72 |doi=10.1016/S0925-5214(00)00079-X }}</ref><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|access-date = 9 August 2006|archive-date = 29 June 2022|archive-url = https://web.archive.org/web/20220629030829/https://www.starchefs.com/events/studio/techniques/FAdria/index.shtml|url-status = live}}</ref> 

The firming effect of calcium chloride can be attributed to several mechanisms:<ref name="p"/>
# Complexation, since calcium ions form complexes with pectin, a polysaccharide found in the cell wall and middle lamella of plant tissues.<ref name="p"/>
# Membrane stabilization, since calcium ions contribute to the stabilization of the cell membrane.<ref name="p"/>
# Turgor pressure regulation, since calcium ions influence cell turgor pressure, which is the pressure exerted by the cell contents against the cell wall.<ref name="p"/>

Calcium chloride's freezing-point depression properties are used to slow the freezing of the caramel in caramel-filled chocolate bars.<ref name="q"/> Also, it is frequently added to sliced apples to maintain texture.<ref>{{cite book |doi=10.1016/B978-0-08-088504-9.00275-0 |chapter=Pre- and Postharvest Treatments Affecting Nutritional Quality |title=Comprehensive Biotechnology |date=2011 |pages=349–357 |isbn=978-0-08-088504-9 | vauthors = Sitbon C, Paliyath G }}</ref>

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.<ref name="q"/>

In [[cheesemaking]], calcium chloride is sometimes added to processed (pasteurized/homogenized) milk to restore the natural balance between calcium and protein in [[casein]]. It is added before the coagulant.<ref name="q"/>

Calcium chloride is also commonly used as an "[[electrolyte]]" in [[sports drink]]s and other beverages; as a [[food additive]] used in conjunction with other inorganic salts it adds taste to [[bottled water]].<ref>{{cite web | url=https://time.com/3029191/bottled-water-ingredients-nutrition-health/ | title=Why Your Bottled Water Contains Four Different Ingredients | date=24 July 2014 | access-date=17 March 2024 | archive-date=8 February 2019 | archive-url=https://web.archive.org/web/20190208133445/http://time.com/3029191/bottled-water-ingredients-nutrition-health/ | url-status=live }}</ref><ref name="q">{{cite book|title=Encyclopedia of the Alkaline Earth Compounds|doi=10.1016/B978-0-444-59550-8.00002-8|chapter=2.2.4|page=51|quote=Calcium chloride is commonly used as an “electrolyte” and has an extremely salty taste, as found in sports drinks and other beverages such as Nestle bottled water.}}</ref><ref>{{Cite web|url=https://waterpurificationguide.com/brands-of-bottled-water-with-electrolytes/|title=Brands Of Bottled Water With Electrolytes (Confirmed By Lab Tests) - Water Purification Guide}}</ref> 

The average intake of calcium chloride as food additives has been estimated to be 160–345&nbsp;mg/day.<ref>Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, pp. 13–14.</ref> Calcium chloride is permitted as a food additive in the [[European Union]] for use as a [[sequestrant]] and [[firming agent]] with the [[E number]] '''E509'''.<ref name="q"/> It is considered as [[generally recognized as safe|generally recognized as safe (GRAS)]] by the U.S. Food and Drug Administration.<ref>21 [[Code of Federal Regulations|CFR]] § 184.1193</ref> Its use in [[Organic farming|organic crop production]] is generally prohibited under the US [[National Organic Program]].<ref name="CFRTitle7Part205Section602c">7 [[Code of Federal Regulations|CFR]] [http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=e967a1968547dfb3141e756cac7ca0ad&h=L&n=7y3.1.1.9.32.7&r=SUBPART&ty=HTML#7:3.1.1.9.32.7.354.3 § 205.602] {{webarchive |url=https://web.archive.org/web/20210429195910/https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=e967a1968547dfb3141e756cac7ca0ad&h=L&n=7y3.1.1.9.32.7&r=SUBPART&ty=HTML#7:3.1.1.9.32.7.354.3 |date=29 April 2021}}</ref>

<!-- Copied information from [[Calcium supplement]], see that page's history for attribution under the CC BY-SA 4.0 License and the GFDL.  -->
Calcium chloride contains approximately 27.2% or 272 mg of elemental calcium per gram. This means that for every gram of calcium chloride, there are 272 mg of actual, absorbable calcium. Calcium chloride has a very salty taste and can cause mouth and throat irritation at high concentrations, so it is typically not the first choice for long-term oral supplementation (as a [[calcium supplement]]).<ref>{{cite web | url=https://www.drugs.com/cdi/calcium-chloride.html | title=Calcium Chloride: Indications, Side Effects, Warnings | access-date=15 March 2024 | archive-date=17 February 2023 | archive-url=https://web.archive.org/web/20230217141037/https://www.drugs.com/cdi/calcium-chloride.html | url-status=live }}</ref><ref name="pmid11165888">{{cite journal |vauthors=Bendich A |title=Calcium supplementation and iron status of females |journal=Nutrition |volume=17 |issue=1 |pages=46–51 |date=January 2001 |pmid=11165888 |doi=10.1016/s0899-9007(00)00482-2 |url=}}</ref> Calcium chloride, characterized by its low molecular weight and high water solubility, readily breaks down into calcium and chloride ions when exposed to water. These ions are efficiently absorbed from the intestine.<ref>{{cite web |url=https://www.industrialchemicals.gov.au/sites/default/files/Calcium%20chloride%20%28CaCl2%29_Human%20health%20tier%20II%20assessment.pdf |title=Archived copy |access-date=16 March 2024 |archive-date=16 March 2024 |archive-url=https://web.archive.org/web/20240316234535/https://www.industrialchemicals.gov.au/sites/default/files/Calcium%20chloride%20(CaCl2)_Human%20health%20tier%20II%20assessment.pdf |url-status=live}}</ref> However, caution should be exercised when handling calcium chloride, for it has the potential to release heat energy upon dissolution in water. This release of heat can lead to trauma and burns in the mouth, throat, [[esophagus]], and stomach. In fact, there have been reported cases of stomach necrosis resulting from burns caused by accidental ingestions of big amounts of dry calcium chloride.<ref>{{cite journal |last1=Remes-Troche |first1=Jose Maria |title=A 'black stomach' due to ingestion of anhydrous calcium chloride |journal=BMJ Case Reports |date=2 January 2013 |pages=bcr2012007716 |doi=10.1136/bcr-2012-007716 |pmid=23283618 |pmc=3604345 }}</ref><ref>{{cite journal |doi=10.14309/crj.0000000000000446 |title=Gastric Necrosis because of Ingestion of Calcium Chloride |date=2020 |journal=ACG Case Reports Journal |volume=7 |issue=8 |pages=e00446 |pmid=32903978 |pmc=7447462 | vauthors = Nakagawa Y, Maeda A, Takahashi T, Kaneoka Y}}</ref>

The extremely [[Saltiness|salty taste]] of calcium chloride is used to flavor [[Pickled cucumber|pickles]] without increasing the food's [[sodium]] content.<ref name="q"/> 

Calcium chloride is used to prevent [[cork spot]] and [[bitter pit]] on apples by spraying on the tree during the late growing season.<ref>"Cork Spot and Bitter Pit of Apples", Richard C. Funt and Michael A. Ellis, Ohioline.osu.edu/factsheet/plpath-fru-01</ref>

===Laboratory and related drying operations===
[[Drying tube]]s are frequently packed with calcium chloride. [[Kelp]] is dried with calcium chloride for use in producing [[sodium carbonate]]. Anhydrous calcium chloride 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 = https://www.fda.gov/ora/compliance_ref/cpg/cpgfod/cpg500-400.html|access-date = 3 December 2007|archive-date = 13 December 2007|archive-url = https://web.archive.org/web/20071213212316/http://www.fda.gov/ora/compliance_ref/cpg/cpgfod/cpg500-400.html|url-status = live}}</ref>

The hydrated salt can be dried for re-use but will dissolve in its own water of hydration if heated quickly and form a hard amalgamated solid when cooled.

=== Metal reduction flux ===
Similarly, {{chem2|CaCl2}} is used as a flux and [[electrolyte]] in the [[FFC Cambridge process|FFC Cambridge electrolysis process]] for [[titanium]] production, where it ensures the proper exchange of calcium and oxygen ions between the electrodes.

=== Medical use ===
Calcium chloride [[Infusion therapy|infusions]] may be used as an [[intravenous therapy]] to prevent [[hypocalcemia]].

===Other applications===
{{More citations needed|section|date=May 2020}}
Calcium chloride is used in concrete mixes to [[Cement accelerator|accelerate]] the initial setting, but chloride ions lead to corrosion of steel [[rebar]], so it should not be used in [[reinforced concrete]].<ref>{{cite web|title = Accelerating Concrete Set Time|publisher = [[Federal Highway Administration]]|date = 1 June 1999|url = http://www.fhwa.dot.gov/infrastructure/materialsgrp/acclerat.htm|access-date = 16 January 2007|archive-date = 17 January 2007|archive-url = https://web.archive.org/web/20070117021146/http://www.fhwa.dot.gov/infrastructure/materialsgrp/acclerat.htm|url-status = dead}}</ref> The anhydrous form of calcium chloride may also be used for this purpose and can provide a measure of the moisture in concrete.<ref>{{cite book|title=Adhesives in Building: Selection and Field Application; Pressure-sensitive Tapes|author=National Research Council (U.S.). Building Research Institute|publisher=National Academy of Science-National Research Council|pages=24–5|year=1962}}</ref>

Calcium chloride is included as an additive in plastics and in [[fire extinguisher]]s, in [[blast furnace]]s 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 pad]]s.

Calcium chloride is used as a water hardener in the maintenance of [[hot tub]] water, as insufficiently hard water can lead to corrosion and foaming.

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

{{chem2|CaCl2}} acts as [[flux (metallurgy)|flux material]], decreasing the melting point, in the Davy process for the industrial production of sodium metal through the [[electrolysis]] of molten NaCl.

Calcium chloride is also used in the production of [[activated charcoal]].

Calcium chloride can be used to precipitate [[fluoride]] [[ions]] from water as insoluble {{chem2|CaF2}}.

Calcium chloride is also an ingredient used in ceramic [[slipware]]. It suspends clay particles so that they float within the solution, making it easier to use in a variety of slipcasting techniques.

Calcium chloride dihydrate (20 percent by weight) dissolved in [[ethanol]] (95 percent ABV) has been used as a [[Animal sterilization|sterilant]] for male animals. The solution is injected into the testes of the animal. Within one month, [[necrosis]] of testicular tissue results in sterilization.<ref>{{cite journal |last1=Koger |first1=L. M. |title=Calcium Chloride, Practical Necrotising Agent |journal=The Bovine Practitioner |date=November 1977 |pages=118–119 |doi=10.21423/bovine-vol1977no12p118-119 }}</ref><ref>{{cite journal |last1=Jana |first1=Kuladip |last2=Samanta |first2=Prabhat K |title=Clinical Evaluation of Non-surgical Sterilization of Male Cats with Single Intra-testicular Injection of Calcium Chloride |journal=BMC Veterinary Research |date=2011 |volume=7 |issue=1 |pages=39 |doi=10.1186/1746-6148-7-39 |doi-access=free |pmid=21774835 |pmc=3152893 }}</ref>

[[Cocaine]] producers in [[Colombia]] import tons of calcium chloride to recover solvents that are on the [[International Narcotics Control Board#Responsibilities under the 1988 Convention|INCB Red List]] and are more tightly controlled.<ref>{{cite web |last1=Smith |first1=Michael |last2=Simpson |first2=Cam |title=Narcos Are Waging a New Drug War Over a Texas Company's Basic Chemical |url=https://www.bloomberg.com/news/features/2020-10-26/tetra-s-tti-calcium-chloride-is-fueling-a-cocaine-war-in-south-america |website=Bloomberg |date=26 October 2020 |access-date=26 October 2020 |archive-date=26 October 2020 |archive-url=https://archive.today/20201026131857/https://www.bloomberg.com/news/features/2020-10-26/tetra-s-tti-calcium-chloride-is-fueling-a-cocaine-war-in-south-america |url-status=bot: unknown }}</ref>

==Hazards==
Although the salt is non-toxic in small quantities when wet, the strongly [[hygroscopic]] properties of non-hydrated calcium chloride present some hazards. It can act as an [[Irritation|irritant]] by [[desiccating]] moist skin. Solid calcium chloride dissolves [[exothermic]]ally, and [[Burn (injury)|burns]] can result in the [[mouth]] and esophagus if it is ingested. Ingestion of concentrated solutions or solid products may cause [[gastrointestinal]] irritation or [[ulceration]].<ref>{{cite web|url = http://www.dow.com/productsafety/finder/cacl_2.htm|title = Product Safety Assessment (PSA): Calcium Chloride|publisher = [[Dow Chemical Company]]|date = 2 May 2006|access-date = 22 July 2008|archive-url = https://web.archive.org/web/20090917163015/http://www.dow.com/productsafety/finder/cacl_2.htm|archive-date = 17 September 2009|url-status = dead}}</ref>

Consumption of calcium chloride can lead to [[hypercalcemia]].<ref>{{cite web|url = https://www.drugs.com/pro/calcium-chloride.html|title = Calcium Chloride Possible Side Affects|work = www.drugs.com|access-date = 23 January 2018|archive-date = 27 July 2020|archive-url = https://web.archive.org/web/20200727064255/https://www.drugs.com/pro/calcium-chloride.html|url-status = live}}</ref>

==Properties==
[[File:Flame Test Ca.jpg|200px|thumbnail|left|[[Flame test]] of {{chem2|CaCl2}}]]
Calcium chloride dissolves in water, producing chloride and the [[aquo complex]] {{chem2|[Ca(H2O)6](2+)}}. In this way, these solutions are sources of "free" calcium and free chloride ions. This description is illustrated by the fact that these solutions react with [[phosphate]] sources to give a solid precipitate of [[calcium phosphate]]:

:{{chem2|3 CaCl2 + 2 PO4(3−) → Ca3(PO4)2 + 6 Cl−}}

Calcium chloride has a very high [[enthalpy change of solution]], indicated by considerable temperature rise accompanying dissolution of the anhydrous salt in water. This property is the basis for its largest-scale application.

Molten calcium chloride can be [[electrolysis|electrolysed]] to give [[calcium]] metal and [[chlorine]] gas:
:{{chem2|CaCl2 → Ca + Cl2}}

==Preparation==
[[File:Ca(aq)6 improved image.tif|thumb|left|Structure of the polymeric {{chem2|[Ca(H2O)6](2+)}} center in crystalline calcium chloride hexahydrate, illustrating the high coordination number typical for calcium complexes.]]

In much of the world, calcium chloride is derived from [[limestone]] as a by-product of the [[Solvay process]], which follows the net reaction below:<ref name=Ullmann/>
:{{chem2|2 NaCl + CaCO3 → Na2CO3 + CaCl2}}
North American consumption in 2002 was 1,529,000 [[tonne]]s (3.37 billion pounds).<ref>Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, page 11.</ref> In the US, most calcium chloride is obtained by purification from [[brine]]. As with most bulk commodity salt products, [[trace element|trace]] amounts of other [[cation]]s from the [[alkali metal]]s and [[alkaline earth metal]]s ([[group (periodic table)|groups]] 1 and 2) and other [[anion]]s from the [[halogen]]s ([[group (periodic table)|group]] 17) typically occur.<ref name=Ullmann/>

===Occurrence===
Calcium chloride occurs as the rare [[evaporite]] minerals sinjarite (dihydrate) and [[antarcticite]] (hexahydrate).<ref>{{Cite web|url=https://www.mindat.org/min-3673.html|title=Sinjarite|work=www.mindat.org|access-date=6 November 2020|archive-date=3 March 2023|archive-url=https://web.archive.org/web/20230303212045/https://www.mindat.org/min-3673.html|url-status=live}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-251.html|title=Antarcticite|work=www.mindat.org|access-date=6 November 2020|archive-date=1 May 2023|archive-url=https://web.archive.org/web/20230501221309/https://www.mindat.org/min-251.html|url-status=live}}</ref><ref name="ima-mineralogy.org">{{Cite web|url=https://www.ima-mineralogy.org/Minlist.htm|title=List of Minerals|date=21 March 2011|work=www.ima-mineralogy.org|access-date=6 November 2020|archive-date=15 March 2013|archive-url=https://web.archive.org/web/20130315004607/https://www.ima-mineralogy.org/Minlist.htm|url-status=live}}</ref> Another natural hydrate known is ghiaraite – a tetrahydrate.<ref>{{Cite web|url=https://www.mindat.org/min-43592.html|title=Ghiaraite|work=www.mindat.org|access-date=6 November 2020|archive-date=3 March 2023|archive-url=https://web.archive.org/web/20230303210545/https://www.mindat.org/min-43592.html|url-status=live}}</ref><ref name="ima-mineralogy.org"/> The related minerals [[chlorocalcite]] (potassium calcium chloride, {{chem2|KCaCl3}}) and [[tachyhydrite]] (calcium magnesium chloride, {{chem2|[[calcium|Ca]][[magnesium|Mg]]2[[chlorine|Cl]]6*12[[water|H2O]]}}) are also very rare.<ref>{{Cite web|url=https://www.mindat.org/min-1020.html|title=Chlorocalcite|work=www.mindat.org|access-date=6 November 2020|archive-date=30 May 2023|archive-url=https://web.archive.org/web/20230530013103/https://www.mindat.org/min-1020.html|url-status=live}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-3865.html|title=Tachyhydrite|work=www.mindat.org|access-date=6 November 2020|archive-date=3 March 2023|archive-url=https://web.archive.org/web/20230303210537/https://www.mindat.org/min-3865.html|url-status=live}}</ref><ref name="ima-mineralogy.org"/> The same is true for rorisite, CaClF (calcium chloride fluoride).<ref>{{Cite web|url=https://www.mindat.org/min-3446.html|title=Rorisite|work=www.mindat.org|access-date=6 November 2020|archive-date=3 March 2023|archive-url=https://web.archive.org/web/20230303210547/https://www.mindat.org/min-3446.html|url-status=live}}</ref><ref name="ima-mineralogy.org"/>

== See also ==
* [[Calcium(I) chloride]]
* [[Calcium chloride transformation]]
* [[Magnesium chloride]]

{{clear}}

==References==
{{reflist|30em}}
*{{Greenwood&Earnshaw}}

==External links==
{{Commons category|Calcium chloride}}
*[https://archive.today/20130415003211/http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc11/icsc1184.htm International Chemical Safety Card 1184]
*[http://www.oxycalciumchloride.com/ Product and Application Information (Formerly Dow Chemical Calcium Chloride division)] {{Webarchive|url=https://web.archive.org/web/20230917030321/https://www.oxycalciumchloride.com/ |date=17 September 2023 }}
*[http://www.dot.state.fl.us/research-center/Completed_Proj/Summary_SMO/FDOT_806.pdf Report on steel corrosion by chloride including CaCl<sub>2</sub>] {{Webarchive|url=https://web.archive.org/web/20110616125122/http://www.dot.state.fl.us/research-center/Completed_Proj/Summary_SMO/FDOT_806.pdf |date=16 June 2011 }}
*[https://web.archive.org/web/20090206162446/http://glchloride.com/links.php Collection of calcium chloride reports and articles]
*[https://web.archive.org/web/20121015090829/http://www.sciencelab.com/msds.php?msdsId=9923251 Calcium chloride, Anhydrous MSDS]
*[http://pubs.acs.org/doi/pdf/10.1021/ja01131a021 Difusivity of calcium chloride]
*[https://www.cdc.gov/niosh/ipcsneng/neng1184.html Centers for Disease Control and Prevention], National Institutes of Occupational Safety and Health, "Calcium Chloride (anhydrous)" 
{{Calcium compounds}}
{{Chlorides}}
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{{Urologicals, including antispasmodics}}
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{{DEFAULTSORT:Calcium Chloride}}
[[Category:Calcium compounds]]
[[Category:Chlorides]]
[[Category:Alkaline earth metal halides]]
[[Category:Deliquescent materials]]
[[Category:Desiccants]]
[[Category:Pyrotechnic colorants]]
[[Category:Edible salt]]
[[Category:E-number additives]]
[[Category:Concrete admixtures]]