calcium chloride

Calcium chloride was apparently discovered in the 15th century but wasn't studied properly until the 18th century.{{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}} It was historically called "fixed sal ammoniac" ({{langx|la|sal ammoniacum fixum}}{{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}}) because it was synthesized during the distillation of ammonium chloride with lime and was nonvolatile (while the former appeared to sublime); in more modern times (18th–19th cc.) it was called "muriate of lime" ({{langx|la|murias calcis, calcaria muriatica}}).{{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}}

{{Main article|De-icing}}

File:Cacl2 storage for winter road in japan.jpg]]

By 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 °C (−62 °F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.{{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 }}

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

{{Main articles|Road salt}}

File:Calcium chloride on a dirt road.jpg, 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 roads, 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 by as much as 50% and the need for fill-in materials as much as 80%.{{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 }}

In the food industry, calcium chloride is frequently employed as a firming agent in canned vegetables, particularly for canned tomatoes and cucumber pickles.{{cite book|title=Handbook of Food Preservation|edition=2nd|editor=M. Shafiur Rahman|publisher=CRC Press|year=2007|isbn=978-1-57444-606-7|url=https://www.cold.org.gr/library/downloads/Docs/Handbook%20of%20Food%20Preservation.PDF|access-date=17 November 2024|archive-date=5 April 2023|archive-url=https://web.archive.org/web/20230405101602/http://www.cold.org.gr/library/downloads/Docs/Handbook%20of%20Food%20Preservation.PDF|url-status=live}}{{cite journal|doi=10.1111/j.1750-3841.2010.01558.x |title=Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride |date=2010 |last1=McFeeters |first1=Roger F. |last2=Pérez-Díaz |first2=Ilenys |journal=Journal of Food Science |volume=75 |issue=3 |pages=C291-6 |pmid=20492282 }}{{cite book|isbn=978-1-936424-26-9|title=Food Chemicals Codex|publisher=The United States Pharmacopeial Convention}}{{cite journal|doi=10.1111/j.1365-2621.1992.tb06859.x |title=Calcium Chloride and Potassium Sorbate Reduce Sodium Chloride used during Natural Cucumber Fermentation and Storage |date=1992 |last1=Guillou |first1=A.A. |last2=Floros |first2=J.D. |last3=Cousin |first3=M.A. |journal=Journal of Food Science |volume=57 |issue=6 |pages=1364–1368 }} It is also used in firming soybean curds into tofu and in producing a caviar substitute from vegetable or fruit juices.{{cite book|isbn=978-1-003-35544-1|title=Emulsification and Spherification|series=Structured Foods|author1=Devanampriyan Rajan|author2=Chitra Devi Venkatachalam|author3=Mahalakshmi R. L. Sruthi|author4=Shaikh Mohd Riyan|publisher=CRC Press|year=2024}}{{cite book|date=13 August 2013|isbn=978-0-231-15345-4 |title=The Kitchen as Laboratory: Reflections on the Science of Food and Cooking |last1=Vega |first1=Cesar |last2=Ubbink |first2=Job |last3=Linden |first3=Erik van der |publisher=Columbia University Press }}{{cite book|date=18 August 2008|isbn=978-0-231-13313-5 |title=Molecular Gastronomy: Exploring the Science of Flavor |last1=This |first1=Hervé |publisher=Columbia University Press }} 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.{{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 }}{{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}}

The firming effect of calcium chloride can be attributed to several mechanisms:

1. Complexation, since calcium ions form coordination complexes with pectin, a polysaccharide found in the cell wall and middle lamella of plant tissues.
2. Membrane stabilization, since calcium ions contribute to the stabilization of the cell membrane.
3. Turgor pressure regulation, since calcium ions influence cell turgor pressure, which is the pressure exerted by the cell contents against the cell wall.

Calcium chloride's freezing-point depression properties are used to slow the freezing of the caramel in caramel-filled chocolate bars.{{citation needed|date=November 2024}} Also, it is frequently added to sliced apples to maintain texture.{{cite book |doi=10.1016/B978-0-08-088504-9.00275-0 |series=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 |chapter=Pre- and Postharvest Treatments Affecting Nutritional Quality |publisher=Academic Press }}

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.{{cite book|isbn=978-0-937381-99-1 |title=Water: A Comprehensive Guide for Brewers |last1=Palmer |first1=John J. |last2=Kaminski |first2=Colin |date=2013 |publisher=Brewers Publications }}{{cite book|isbn=978-1-85573-490-6 |title=Brewing: Science and Practice |last1=Briggs |first1=Briggs |last2=Boulton |first2=Chris|last3=Brooke|first3=Peter |date=28 September 2004 |publisher=Woodhead Publishing Ltd }}{{cite book|doi=10.1533/9781845691738.183 |series=Water in brewing |title=Brewing |date=2006 |last1=Eumann |first1=M. |chapter=Water in brewing |pages=183–207 |isbn=978-1-84569-003-8 }}{{cite book|doi=10.1007/978-1-4615-0729-1_4 |series=Water for brewing |title=Brewing |date=2001 |last1=Lewis |first1=Michael J. |last2=Young |first2=Tom W. |pages=57–70 |isbn=978-0-306-47274-9 }}{{cite book|isbn=978-0-8247-2763-5 |title=Dairy Science and Technology, Second Edition |last1=Walstra |first1=P. |last2=Walstra |first2=Pieter |last3=Wouters |first3=Jan T. M. |last4=Geurts |first4=Tom J. |date=29 September 2005 |publisher=Taylor & Francis }}

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.{{cite book| doi=10.1007/978-1-4899-7681-9|isbn=978-1-4899-7681-9 |title=Fundamentals of Cheese Science |date=2017 |last1=Fox |first1=Patrick F. |last2=Guinee |first2=Timothy P. |last3=Cogan |first3=Timothy M. |last4=McSweeney |first4=Paul L. H. |publisher=Springer US}}

Calcium chloride is also commonly used as an "electrolyte" in sports drinks and other beverages; as a food additive used in conjunction with other inorganic salts it adds taste to bottled water.{{cite web | url=https://products.lab-suppliers.com/product/calcium-chloride-dihydrate-ep-table-water-25kg | title=Lab Suppliers: Calcium chloride dihydrate extra pure, for table water FCC, E 509. CAS 10035-04-8, pH 4.5 - 8.5 (50 g/l, H₂O, 20 °C)}}{{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 }}{{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|access-date=4 July 2024|archive-date=24 October 2021|archive-url=https://web.archive.org/web/20211024012321/https://waterpurificationguide.com/brands-of-bottled-water-with-electrolytes/|url-status=live}}

The average intake of calcium chloride as food additives has been estimated to be 160–345 mg/day.Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, pp. 13–14. 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.{{cite web|url=https://www.food.gov.uk/business-guidance/approved-additives-and-e-numbers|title=Current EU approved additives and their E Numbers|archive-url=https://web.archive.org/web/20220422201759/https://www.food.gov.uk/business-guidance/approved-additives-and-e-numbers|archive-date=22 April 2022|publisher=Food Standards Agency|access-date=17 November 2024}} It is considered as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration.21 CFR § 184.1193 Its use in organic crop production is generally prohibited under the US National Organic Program.7 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}}

The elemental calcium content in calcium chloride hexahydrate (CaCl₂·6H₂O) is approximately 18.2%. This means that for every gram of calcium chloride hexahydrate, there are about 182 milligrams of elemental calcium.

For anhydrous calcium chloride (CaCl₂), the elemental calcium content is almost twice higher, that is around 36.1% (for every gram of anhydrous calcium chloride there are about 361 milligrams of elemental 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).{{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 }}{{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=}} 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.{{cite web |url=https://www.industrialchemicals.gov.au/sites/default/files/Calcium%20chloride%20%28CaCl2%29_Human%20health%20tier%20II%20assessment.pdf |title= Calcium chloride (CaCl2): Human health tier II assessment |access-date=16 March 2024|date= 27 November 2014 |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}} Calcium chloride 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 undissolved calcium chloride.{{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 }}{{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}}

The extremely salty taste of calcium chloride is used to flavor pickles without increasing the food's sodium content.{{cite journal|doi=10.1155/2018/8051435 |title=Quality of Cucumbers Commercially Fermented in Calcium Chloride Brine without Sodium Salts |date=2018 |last1=McMurtrie |first1=Erin K. |last2=Johanningsmeier |first2=Suzanne D. |journal=Journal of Food Quality |pages=1–13 |doi-access=free |s2cid=54004105 }}

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

Drying tubes 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).{{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}}

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.

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

Calcium chloride infusions may be used as an intravenous therapy to prevent hypocalcemia.{{cite book|title=Harrison's Principles of Internal Medicine|isbn=978-1-264-26850-4 |last1=Loscalzo |first1=Joseph |last2=Fauci |first2=Anthony S. |last3=Kasper |first3=Dennis L. |last4=Hauser |first4=Stephen L. |last5=Longo |first5=Dan Louis |last6=Larry Jameson |first6=J. |date=2022 |publisher=McGraw Hill }}{{cite journal|doi=10.1038/nrm1154 |title=Extracellular calcium sensing and signalling |date=2003 |last1=Hofer |first1=Aldebaran M. |last2=Brown |first2=Edward M. |journal=Nature Reviews Molecular Cell Biology |volume=4 |issue=7 |pages=530–538 |pmid=12838336 }}{{cite journal|doi=10.4158/EP-2018-0524 |title=Clinical Characteristics of Patients with Type 2 Diabetes Mellitus Continued on Oral Antidiabetes Medications in the Hospital |date=2020 |journal=Endocrine Practice |volume=26 |issue=2 |pages=167–173 |pmid=31557075 | vauthors = Amir M, Sinha V, Kistangari G, Lansang MC }}{{cite book|title=Hypocalcemia: Diagnosis and Treatment|date=2000 |pmid=25905251 |last1=Feingold |first1=K. R. |last2=Anawalt |first2=B. |last3=Blackman |first3=M. R. |last4=Boyce |first4=A. |last5=Chrousos |first5=G. |last6=Corpas |first6=E. |last7=De Herder |first7=W. W. |last8=Dhatariya |first8=K. |last9=Dungan |first9=K. |last10=Hofland |first10=J. |last11=Kalra |first11=S. |last12=Kaltsas |first12=G. |last13=Kapoor |first13=N. |last14=Koch |first14=C. |last15=Kopp |first15=P. |last16=Korbonits |first16=M. |last17=Kovacs |first17=C. S. |last18=Kuohung |first18=W. |last19=Laferrère |first19=B. |last20=Levy |first20=M. |last21=McGee |first21=E. A. |last22=McLachlan |first22=R. |last23=New |first23=M. |last24=Purnell |first24=J. |last25=Sahay |first25=R. |last26=Shah |first26=A. S. |last27=Singer |first27=F. |last28=Sperling |first28=M. A. |last29=Stratakis |first29=C. A. |last30=Trence |first30=D. L. |display-authors=1 }}{{cite book|title=Goodman and Gilman's The Pharmacological Basis of Therapeutics|isbn=978-1-264-25807-9 |last1=Brunton |first1=Laurence L. |last2=Knollmann |first2=Björn C. |date=2022 |publisher=McGraw Hill }}

Calcium chloride is a highly soluble calcium salt. Hexahydrate calcium chloride (CaCl₂·6H₂O) has solubility in water of 811 g/L at 25 °C. Calcium chloride when taken orally completely dissociates into calcium ions (Ca²⁺) in the gastrointestinal tract, resulting in readily bioavailable calcium. The high concentration of calcium ions facilitates efficient absorption in the small intestine. However, the use of calcium chloride as a source of calcium taken orally is less common compared to other calcium salts because of potential adverse effects such as gastrointestinal irritation and discomfort.{{cite journal |vauthors=Heaney RP, Recker RR, Weaver CM |title=Absorbability of calcium sources: the limited role of solubility |journal=Calcif Tissue Int |volume=46 |issue=5 |pages=300–4 |date=May 1990 |pmid=2110852 |doi=10.1007/BF02563819 |url=}}{{cite journal |vauthors=Straub DA |title=Calcium supplementation in clinical practice: a review of forms, doses, and indications |journal=Nutr Clin Pract |volume=22 |issue=3 |pages=286–96 |date=June 2007 |pmid=17507729 |doi=10.1177/0115426507022003286 |url=}}{{cite book|pmid=21796828|doi=10.17226/13050 |title=Dietary Reference Intakes for Calcium and Vitamin D |date=2011 |isbn=978-0-309-16394-1 |author1=Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium |last2=Ross |first2=A. C. |last3=Taylor |first3=C. L. |last4=Yaktine |first4=A. L. |last5=Del Valle |first5=H. B. }}

When tasted, calcium chloride exhibits a distinctive bitter flavor alongside its salty taste. The bitterness is attributable to the calcium ions and their interaction with human taste receptors: certain members of the TAS2R family of bitter taste receptors respond to calcium ions; the bitter perception of calcium is thought to be a protective mechanism to avoid ingestion of toxic substances, as many poisonous compounds taste bitter. While chloride ions (Cl⁻) primarily contribute to saltiness, at higher concentrations, they can enhance the bitter sensation. The combination of calcium and chloride ions intensifies the overall bitterness. At lower concentrations, calcium chloride may taste predominantly salty. The salty taste arises from the electrolyte nature of the compound, similar to sodium chloride (table salt). As the concentration increases, the bitter taste becomes more pronounced: the increased presence of calcium ions enhances the activation of bitterness receptors.{{cite journal |vauthors=Chandrashekar J, Hoon MA, Ryba NJ, Zuker CS |title=The receptors and cells for mammalian taste |journal=Nature |volume=444 |issue=7117 |pages=288–94 |date=November 2006 |pmid=17108952 |doi=10.1038/nature05401|bibcode=2006Natur.444..288C }}{{cite journal|title=Calcium: Taste, Intake, and Appetite|author=Michael G. Tordoff|journal=Physiological Reviews |date=10 January 2001|volume=81 |issue=4 |pages=1567–1597 |doi=10.1152/physrev.2001.81.4.1567|pmid=11581497 }}{{cite journal |vauthors=Breslin PA, Beauchamp GK |title=Salt enhances flavour by suppressing bitterness |journal=Nature |volume=387 |issue=6633 |pages=563 |date=June 1997 |pmid=9177340 |doi=10.1038/42388|bibcode=1997Natur.387..563B }}

{{More citations needed|section|date=May 2020}}

Calcium chloride is used in concrete mixes to accelerate the initial setting, but chloride ions lead to corrosion of steel rebar, so it should not be used in reinforced concrete.{{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}} The anhydrous form of calcium chloride may also be used for this purpose and can provide a measure of the moisture in concrete.{{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}}

Calcium chloride is included as an additive in plastics and in fire extinguishers, 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.{{citation needed|date=November 2024}}

The exothermic dissolution of calcium chloride is used in self-heating cans and heating pads.{{citation needed|date=November 2024}}

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.{{citation needed|date=November 2024}}

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.{{citation needed|date=November 2024}}

Calcium chloride ({{chem|Ca|Cl|2}}) acts as flux material, decreasing the melting point, in the Davy process for the industrial production of sodium metal through the electrolysis of molten {{chem|Na|Cl}}.{{citation needed|date=November 2024}}

Calcium chloride is also used in the production of activated charcoal.{{citation needed|date=November 2024}}

Calcium chloride can be used to precipitate fluoride ions from water as insoluble {{chem|Ca|F|2}}.{{citation needed|date=November 2024}}

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.{{citation needed|date=November 2024}}

For watering plants to use as a fertilizer, a moderate concentration of calcium chloride is used to avoid potential toxicity: 5 to 10 mM (millimolar) is generally effective and safe for most plants—that is {{convert|0.55|-|1.11|g}} of anhydrous calcium chloride ({{chem|Ca|Cl|2}}) per liter of water or {{convert|1.10|-|2.19|g}} of calcium chloride hexahydrate ({{chem|Ca|Cl|2}}·6{{chem|H|2|O}}) per liter of water.{{cite journal|date=2 July 2013|doi=10.1371/journal.pone.0068214|doi-access=free |title=The Effect of Calcium Chloride on Growth, Photosynthesis, and Antioxidant Responses of Zoysia japonica under Drought Conditions |last1=Xu |first1=Chengbin |last2=Li |first2=Xuemei |last3=Zhang |first3=Lihong |journal=PLOS ONE |volume=8 |issue=7 |pages=e68214 |pmid=23844172 |pmc=3699550 |bibcode=2013PLoSO...868214X }}{{cite journal|doi=10.1007/s10725-017-0273-4|date=13 April 2017 |title=Calcium chloride improves photosynthesis and water status in the C4 succulent xerophyte Haloxylon ammodendron under water deficit |last1=Kang |first1=Jianjun |last2=Zhao |first2=Wenzhi |last3=Zheng |first3=Ying |last4=Zhang |first4=Dong Mei |last5=Zhou |first5=Hong |last6=Sun |first6=Pengcheng |journal=Plant Growth Regulation |volume=82 |issue=3 |pages=467–478 }} Calcium chloride solution is used immediately after preparation to prevent potential alterations in its chemical composition.{{cite journal |last1=Hepler |first1=Peter K. |title=Calcium: A Central Regulator of Plant Growth and Development |journal=The Plant Cell |volume=17 |issue=8 |year=2005 |pages=2142–2155 |doi=10.1105/tpc.105.032508 |pmid=16024507|bibcode=2005PlanC..17.2142H |pmc=1182479 }}{{cite book |last1=Taiz |first1=Lincoln |last2=Zeiger |first2=Eduardo |title=Plant Physiology and Development |edition=6th |publisher=Sinauer Associates |year=2015 |isbn=978-1-60535-255-8 |pages=157–159}} Besides that, calcium chloride is highly hygroscopic, meaning it readily absorbs moisture from the air.{{cite journal |last1=Perry |first1=Dale L. |last2=Phillips |first2=Steven L. |title=Handbook of Inorganic Compounds |journal=CRC Press |year=2016 |isbn=978-1-4398-1462-8 |pages=98–99}} If the solution is left standing, it can absorb additional water vapor, leading to dilution and a decrease in the intended concentration. Prolonged standing may lead to the precipitation of calcium hydroxide or other insoluble calcium compounds, reducing the availability of calcium ions in the solution{{cite book |last1=Marschner |first1=Petra |title=Marschner's Mineral Nutrition of Higher Plants |edition=3rd |publisher=Academic Press |year=2012 |isbn=978-0-12-384905-2 |pages=135–137}} and reducing the effectiveness of the solution as a calcium source for plants. Nutrient solutions can become a medium for microbial growth if stored for extended periods.{{cite journal |last1=Jiao |first1=Wei |last2=Zhou |first2=Wei |last3=Tan |first3=Dongxu |title=Effects of Calcium Chloride on Microbial Community and Function in Rhizosphere Soil of Tomato Plants |journal=Frontiers in Microbiology |volume=10 |year=2019 |issue=2 |pages=250–259 |doi=10.3389/fmicb.2019.02052 |doi-access=free |pmid=31543892|pmc=6738277 }} Microbial contamination may alter the composition of the solution and potentially introduce pathogens to the plants. When dissolved in water, calcium chloride can undergo hydrolysis, especially over time, which can lead to the formation of small amounts of hydrochloric acid and calcium hydroxide: {{chem|Ca|2|+}}+2{{chem|H|2|O}} ⇌ {{chem|Ca|(OH)|2}}+2{{chem|H|+}}. This reaction can lower the pH of the solution, making it more acidic.{{cite journal |last1=White |first1=P. J. |last2=Broadley |first2=M. R. |title=Calcium in Plants |journal=Annals of Botany |volume=92 |issue=4 |year=2003 |pages=487–511 |doi=10.1093/aob/mcg164 |pmid=12933363|pmc=4243668 }} Acidic solutions may harm plant tissues and disrupt nutrient uptake.{{cite journal |last1=Kirkby |first1=Edward A. |title=Functional Aspects of Minerals in Plant Metabolism |journal=Encyclopedia of Plant Physiology |volume=15 |year=1981 |pages=679–698 |doi=10.1007/978-3-642-68090-8_30|doi-broken-date=24 November 2024 }}

Calcium chloride dihydrate (20 percent by weight) dissolved in ethanol (95 percent ABV) has been used as a sterilant for male animals. The solution is injected into the testes of the animal. Within one month, necrosis of testicular tissue results in sterilization.{{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 |doi-broken-date=3 December 2024 }}{{Primary source inline|date=November 2024}}{{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 }}{{Primary source inline|date=November 2024}}{{Primary source inline|plural=yes|date=November 2024}}

Cocaine producers in Colombia import tons of calcium chloride to recover solvents that are on the INCB Red List and are more tightly controlled.{{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=24 November 2024 |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=live }}

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 irritant by desiccating moist skin. Solid calcium chloride dissolves exothermically, and 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.{{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}}

Consumption of calcium chloride can lead to hypercalcemia.{{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}}

File:Flame Test Ca.jpg 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.

Aqueous solutions of calcium chloride tend to be slightly acidic due to the influence of the chloride ions on the hydrogen ion concentration in water. The slight acidity of calcium chloride solutions is primarily due to the increased ionic strength of the solution, which can influence the activity of hydrogen ions and lower the pH slightly. The pH of calcium chloride in aqueous solution is the following:{{cite book|isbn=978-1-259-58609-5 |title=Lange's Handbook of Chemistry, Seventeenth Edition |date=5 October 2016 |publisher=McGraw-Hill Education | vauthors = Speight J }}{{cite book|isbn=978-1-032-65562-8 |title=CRC Handbook of Chemistry and Physics |date=4 June 2024 |publisher=CRC Press | vauthors = Rumble JR }}

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

:{{chem2|CaCl2 → Ca + Cl2}}

File:Ca(aq)6 improved image.tif

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:

:{{chem2|2 NaCl + CaCO3 → Na2CO3 + CaCl2}}

North American consumption in 2002 was 1,529,000 tonnes (3.37 billion pounds).Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, page 11. In the US, most calcium chloride is obtained by purification from brine. As with most bulk commodity salt products, trace amounts of other cations from the alkali metals and alkaline earth metals (groups 1 and 2) and other anions from the halogens (group 17) typically occur.

Calcium chloride occurs as the rare evaporite minerals sinjarite (dihydrate) and antarcticite (hexahydrate).{{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}}{{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}}{{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}} Another natural hydrate known is ghiaraite – a tetrahydrate.{{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}} The related minerals chlorocalcite (potassium calcium chloride, {{chem2|KCaCl3}}) and tachyhydrite (calcium magnesium chloride, {{chem2|Ca Mg2Cl6*12H2O}}) are also very rare.{{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}}{{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}} The same is true for rorisite, CaClF (calcium chloride fluoride).{{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}}

• Calcium(I) chloride
• Calcium chloride transformation
• Magnesium chloride
• Calcium supplement

{{clear}}

{{reflist|30em}}

• {{Greenwood&Earnshaw}}

{{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 CaCl₂] {{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)"

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