Calcium Chloride (CaCl2) is a water soluble ionic crystal with a high enthalpy change of solution. It is majorly derived from limestone and is a by-product of the Solvay process. It is an anhydrous salt that has a hygroscopic nature and can be used as a desiccant. Chemical Properties：Calcium chloride, CaC12, is colorless deliquescent solid that is soluble in water and ethanol. It is formed from the reaction of calcium carbonate and hydrochloric acid or calcium hydroxide and ammonium chloride. It is used in medicine, as an antifreeze, and as a coagulant.