Calcium chloride is a chemical substance composed of chlorine and calcium elements, with the chemical formula CaCl2 and a slight bitterness. It is a typical ionic halide, appearing as white, hard fragments or particles at room temperature. Its common applications include saltwater used in refrigeration equipment, road deicing agents, and desiccants.
Physical property:
Colorless cubic crystal, white or grayish white, available in granular, honeycomb block, spherical, irregular granular, and powder forms. Slightly toxic, odorless, and slightly bitter in taste. Highly hygroscopic, easily deliquescent when exposed to air. Easy to dissolve in water, with a solubility of 74.5 g/100g water at 20 ℃, while releasing a large amount of heat (the enthalpy of dissolution of calcium chloride is -176.2 cal/g), its aqueous solution is slightly acidic. Easy to dissolve in various polar and protonic solvents, solubility in the following solvents at 20 ℃ (g/100mL solvent): methanol: 29.2, anhydrous ethanol: 25.8, n-propanol: 15.8, n-butanol: 25.0, n-pentanol: 11.5, ethylene glycol: 21.6 (25 ℃), formic acid: 43.1, acetic acid: 15.0 (30 ℃), hydrazine: 16.0. However, in dipole solvents and low polarity solvents such as ether and tetrahydrofuran, they are only slightly soluble or poorly soluble. Reacting with ammonia or alcohol, CaCl2 · 8NH3 and CaCl2 · 4C2H5OH complexes are formed, respectively. At low temperatures, the solution crystallizes and precipitates into hexahydrate. As it gradually heats up to 30 ℃, it dissolves in its own crystal water and gradually loses water upon further heating. At 200 ℃, it becomes dihydrate, and when heated up to 260 ℃, it becomes white porous anhydrous calcium chloride. During the heating and dehydration process of hydrated calcium chloride, some hydrolysis reactions occur, resulting in the presence of small amounts of CaO impurities in the product.
Chemical property:
antidote:
The pH value of the 5% aqueous solution is 4.5~9.2. 1.7% aqueous solution is isotonic with serum. This product is made from calcium carbonate and hydrochloric acid as raw materials, and is an antidote for magnesium poisoning. Calcium ions can form insoluble calcium fluoride with fluoride, which is used for the rescue of fluorosis.
Calcium chloride with high solubility can undergo a double decomposition reaction to form a precipitate with lower solubility.