Zinc Chloride

Zinc chloride (formerly known in Hungarian as horganyhalvag) is a compound formed with chlorine and zinc, its chloride. Its formula is ZnCl2. It is a white powder and highly hygroscopic. In air, it quickly turns into a dense liquid, forming a concentrated solution. It is very soluble in water: 367 g dissolves in 100 g of water at 20 °C, and 614 g at 100 °C. It is also soluble in alcohol, glycerin, and ether. Aqueous zinc chloride solution has a caustic, metallic taste. The solution hydrolyzes, resulting in a strongly acidic reaction. Multiple hydrates exist, containing one, one and a half, two, or three molecules of crystallization water.

Concentrated zinc chloride solution is used as an etching agent. Because it is highly hygroscopic, it is applied to promote organic chemical reactions that involve water removal. Its solution is also used for wood preservation: it has antibacterial and antifungal properties, and it transforms cellulose fibers, surrounding them with a continuous layer that protects the wood from atmospheric effects. Dentists use it as a hemostatic agent.