Calcium chloride

Calcium chloride is a white, crystalline salt. The anhydrous form is hygroscopic, deliquescent, highly soluble in water, and soluble in some polar organic solvents like acetic acid, alcohols, and pyridine, but insoluble in liquid ammonia and DMSO. Anhydrous calcium chloride has a large enthalpy of dissolution in water, giving off heat when dissolved, which makes it useful in heating pads. Anhydrous calcium chloride can be prepared by several routes. One route involves treating limestone (CaCO₃) with sodium chloride or hydrochloric acid and subsequently precipitating the carbonates with a barium salt. Another route is to purify brine. In both routes, the wet CaCl₂ is then chemically purified and dried. Industrially this is done usually in spray drying towers or fluidized bed dryers.

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Anhydrous calcium chloride is used in a multitude of applications. Scientists have found that molten CaCl₂ is an excellent flux material in molten-salt electrolysis of oxides, due to it high solubility of oxygen anions. Most notably, molten CaCl₂ is used in the electrochemical production of titanium from titanium dioxide[] in the FFC Cambridge process. Similarly, it has been used to produce pure silicon, uranium, vanadium and a host of metals.


CaCl₂ is also used as the calcium source in the synthesis of hydroxyapatites (calcium phosphates), which are found naturally in tooth enamel, and are of interest in chemistry, biology, medicine, and geology.


CaCl₂ is commonly used in the preparation of calcium alginate gel beads, which can serve as a substrate for nanoparticle synthesis.

CaCl₂ has been found to act as a Lewis base catalyst in organic solvents or aqueous conditions:


-Activating DMS enolates


-In chiral oxazoline-metal complexes for stereoselective syntheses


Anhydrous calcium chloride is also used as a drying agent in labs and shipping containers.


Anhydrous calcium chloride is sometimes added to concrete mixes because the heat given off by the dissolution of CaCl₂ accelerates the setting of the concrete.

Calcium chloride in Redi-Dri™ offers several benefits


-Longer shelf-life as a free-flowing powder without addition of anti-caking agents


-Slower absorption of environmental moisture due to beaded form and Redi-Dri packaging


-Conveniently resealable storage container in contrast to ampule


-Faster dissolution compared to clumped materials


-No need to chip, chisel, or grind clumped salts


-Reduced static buildup due to the beads’ lower surface area to volume ratio compared to powder


-increased crucible packing densities compared to powder -lower volatility in high temperature solid state processes compared to powder -convenient delivery of beads to sample chambers through pneumatic loading, which prevents settling and clogging issues normally associated with their powder counterparts


-While the Redi-Dri^™ packaging system does offer desiccating properties, opening and closing of the Redi-Dri^™ bottle is still intended to occur under controlled atmosphere to maintain the highest quality of your MilliporeSigma product.

Redi Dri^™ is an innovative packaging system that prevents absorption of environmental moisture by anhydrous & hydroscopic salts during transport and chemical storage without addition of anti-caking agents, preserving the compounds′ quality assured, free-flowing nature. Redi-Dri^™ also provides a conveniently resealable storage container as a simpler and safer-to-use alternative to one-time-use packaging such as ampules.


While the Redi-Dri^™ packaging system does offer desiccating properties, opening and closing of the Redi-Dri^™ bottle is still intended to occur under controlled atmosphere to maintain the highest quality of your MilliporeSigma product.

Redi-Dri is a trademark of Sigma-Aldrich Co. LLC