Salts of 2− and 2− ions Ī number of salts containing the tetrachlorozincate anion, 2−, are known. Molten anhydrous ZnCl 2 at 500–700 ☌ dissolves zinc metal, and, on rapid cooling of the melt, a yellow diamagnetic glass is formed, which Raman studies indicate contains the Zn 2+ 2 ion. Finally, the simplest method relies on treating the zinc chloride with thionyl chloride. Anhydrous samples can be purified by sublimation in a stream of hydrogen chloride gas, followed by heating the sublimate to 400 ☌ in a stream of dry nitrogen gas. Such samples may be purified by recrystallization from hot dioxane. Unlike many other elements, zinc essentially exists in only one oxidation state, 2+, which simplifies the purification of the chloride.Ĭommercial samples of zinc chloride typically contain water and products from hydrolysis as impurities. ZnS + 2 HCl + 4 H 2O → ZnCl 2(H 2O) 4 + H 2S Hydrated forms and aqueous solutions may be readily prepared similarly by treating Zn metal, zinc carbonate, zinc oxide, and zinc sulfide with hydrochloric acid: Preparation and purification Īnhydrous ZnCl 2 can be prepared from zinc and hydrogen chloride: The tetrahydrate ZnCl 2(H 2O) 4 crystallizes from aqueous solutions of zinc chloride. In the gas phase, ZnCl 2 molecules are linear with a bond length of 205 pm.įive hydrates of zinc chloride are known: ZnCl 2(H 2O) n with n = 1, 1.5, 2.5, 3 and 4. Neutron scattering study indicated the presence of tetrahedral ZnCl 4 centers, which requires aggregation of ZnCl 2 monomers as well. As indicated by a Raman scattering study, the viscosity is explained by the presence of polymers.

Molten ZnCl 2 has a high viscosity at its melting point and a comparatively low electrical conductivity, which increases markedly with temperature. Rapid cooling of molten ZnCl 2 gives a glass. A possible explanation is that the OH − ions originating from the absorbed water facilitate the rearrangement. The orthorhombic form (δ) rapidly changes to one of the other forms on exposure to the atmosphere. Here a, b, and c are lattice constants, Z is the number of structure units per unit cell, and ρ is the density calculated from the structure parameters. Each case features tetrahedral Zn 2+ centers.

H 2O.įour crystalline forms ( polymorphs) of ZnCl 2 are known: α, β, γ, and δ.

No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn 5(OH) 8Cl 2 Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. This salt is hygroscopic and even deliquescent.

Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride. Zinc chloride, anhydrous and its hydrates are colorless or white crystalline solids, and are highly soluble in water. Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl 2.

Zinc reactivity