- Written By
Sahana Soma Kodarkar
- Last Modified 25-01-2023
Zinc Chloride Formula – Definition, Structure, Properties and Uses
Zinc Chloride Formula: In chemical compounds, zinc almost exclusively has the oxidation state \( + 2\,\) Some \( + 1\) state zinc compounds have been reported, but never \( + 3\) state zinc compounds or higher. Zinc chloride is one of the compounds of zinc with oxidation state \( + 2\,\). Zinc chloride is a white crystalline solid at room temperature. Simonkolleite, \({\rm{Z}}{{\rm{n}}_5}{{\rm{(OH)}}_{\rm{8}}}{\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{.}}{{\rm{H}}_{\rm{2}}}{\rm{O}}\) is the very rare mineral of zonc chloride. Zinc chloride is widely used in textile processing, metallurgical fluxes, and chemical synthesis. To learn more about zinc chloride, read the below article.
Define Zinc Chloride
Zinc chloride is the name given to chemical compounds with the formula \({\rm{ZnC}}{{\rm{l}}_{\rm{2}}}.\) Zinc chlorides are colourless or white and extremely soluble in water. There are nine crystalline forms of zinc chlorides. It is deliquescent and hygroscopic. In textile processing, metallurgical fluxes, and chemical synthesis, zinc chloride is widely used.
Lattice of Zinc Chloride
Zinc chloride is a binary inorganic salt. Ionic bonding exists between the zinc cation \(({\rm{ Z}}{{\rm{n}}^2}^ + )\) and the chloride anions \(({\rm{C}}{{\rm{l}}^ – })\) in a zinc chloride molecule. It has a Sphalerite structure in \({\rm{FCC}}\) form in which the cations are present in alternate tetrahedral voids, and the anions are present at the lattice sites.
Preparation of Zinc Chloride
I. Anhydrous zinc chloride can be prepared by the reaction between zinc and hydrogen chloride gas. The chemical reaction that occurred is as follows:
\({\rm{Zn + 2HCl}} \to {\rm{ZnC}}{{\rm{l}}_2} + {{\rm{H}}_2}\)
II. Hydrated forms and aqueous solutions can be easily made by treating zinc metal, zinc carbonate, zinc oxide, and zinc sulphide with hydrochloric acid in the following way:
\({\rm{ZnS + 2HCl + 4}}{{\rm{H}}_2}{\rm{O}} \to {\rm{ZnC}}{{\rm{l}}_2} + {\left( {{{\rm{H}}_2}{\rm{O}}} \right)_4} + {{\rm{H}}_2}{\rm{S}}\)
Purification
Unlike many other elements, zinc essentially only exists in an oxidation state, \(2 + \), which simplifies chloride purification. Commercially available zinc chloride samples typically contain water and hydrolysis products as impurities. These samples can be purified by recrystallization from hot dioxane. Anhydrous samples can be purified by sublimation in a stream of gaseous hydrogen chloride and then heating the sublimate to \(400\,^\circ {\rm{C}}\) in a stream of dry nitrogen gas. Finally, the simplest method is to treat the zinc chloride with thionyl chloride.
Properties of Zinc Chloride
Physical Properties
- Zinc Chloride is solid at room temperature, odourless and has a white crystalline appearance.
- The molar mass of zinc chloride is \(136.315\) grams per mole.
- The density of zinc chloride is \(2.907\) grams per cubic centimetre.
- The melting point and boiling point of zinc chloride is \(563\, {\rm{K}}\) and \(1005\, {\rm{K}}\) respectively.
- The solubility of zinc chloride in water corresponds to \(430\, {\rm{g}}/100\,{\rm{ml}}\). It is also soluble in acetone, ethanol, and glycerin.
- Molten zinc chloride has a relatively low electrical conductivity value and is highly viscous.
- The four polymorphs of \({\rm{ZnC}}{{\rm{l}}_2}\) represent the geometry of the tetrahedral coordinates between the \({\rm{Z}}{{\rm{n}}^{2 + }}\) and \({\rm{Cl}}\) ions.
Chemical Properties
- When \({\rm{ZnC}}{{\rm{l}}_2}\) dissolves in water, the zinc chloride solution formed is acidic.
- When zinc chloride is heated, the hydrated form of zinc chloride loses water and \({\rm{ZnCl(OH)}}\) is formed.
a. The chemical reaction is as follows:
b. Equation - Zinc chloride reacts with ammonia to form complexes such as \({\rm{ZnC}}{{\rm{l}}_2}.2{{\rm{H}}_{\rm{2}}}{\rm{O}} \to {\rm{ZnCl(OH)}} + {{\rm{H}}_{\rm{2}}}{\rm{O + HCl}}\).
Uses of Zinc chloride
Zinc chloride is used as a flux/cleaning agent for soldering because it combines with metal oxides to produce compounds with the general formula \({\rm{MZnOC}}{{\rm{l}}_2}\)(where \({\rm{M}}\) is the metal). These fluxes have the power to dissolve the oxide layer on the metal’s surface. This chemical has a variety of different applications, which are described below.
- It is used in organic synthesis: Zinc chloride is a lewis acid. Therefore it is used in organic chemistry. In the molten state, it acts as a catalyst. This catalyses the conversion of methanol to hexamethylbenzene. \(15{\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{OH}} \to {{\rm{C}}_6}{({\rm{C}}{{\rm{H}}_3})_6} + 3{\rm{C}}{{\rm{H}}_4} + 15{{\rm{H}}_2}O\)
- It is used as a metallurgical flux: It is used as a flux in the welding process and as a cleaning agent. It is also used in the manufacture of magnesia cement.
- It is used in fingerprint detection: Ninhydrin reacts with amino acids and amines to form a “Ruhemann purple” \({\rm{(RP)}}\) coloured compound. Spraying with a zinc chloride solution forms a \(1:1\) or \({\rm{RP:ZnCl}}{({{\rm{H}}_2}{\rm{O}})_2}\) complex, which is easier to detect because it has a more intense fluorescence than \({\rm{RP}}\).
- It is used in textile and paper processing: Concentrated aqueous solutions of zinc chloride can dissolve starch, silk and cellulose. Due to its affinity for these materials, \({\rm{ZnCl}}\) is used as a fire retardant and in fabric “air fresheners” such as Febreze. Vulcanized fibre is made by soaking paper in concentrated zinc chloride.
- It is used as a disinfectant, and wood preservative: Dilute aqueous zinc chloride under the name “Burnett’s Disinfecting Fluid” was used as a disinfectant. It is also used as a wood preservative.
- It is used as smoke grenades: Zinc chloride vapours used in smoke grenades contain zinc oxide, hexachloroethane and granular aluminium powder, which, when ignited, react to form zinc chloride, carbon and alumina vapours – an effective smokescreen.
Summary
Zinc chloride is the name given to chemical compounds with the formula \({\rm{ZnC}}{{\rm{l}}_2}\). Zinc chloride is colourless or white and extremely soluble in water. Zinc chloride is a binary inorganic salt. Anhydrous zinc chloride can be prepared by the reaction between zinc and hydrogen chloride gas. The melting point and boiling point of zinc chloride is \(563\, {\rm{K}}\) and\(1005\, {\rm{K}}\) , respectively. Zinc chloride is solid at room temperature, odourless and has a white crystalline appearance. It has many industrial applications such as is used as smoke grenades, in organic synthesis, etc.
Q.1.What is zinc chloride in chemistry?
Ans: Zinc chloride is the name given to chemical compounds with the formula \({\rm{ZnC}}{{\rm{l}}_2}\). Zinc chlorides are colourless or white and extremely soluble in water.
Q.2. How is zinc chloride formed?
Ans: Anhydrous zinc chloride can be prepared by the reaction between zinc and hydrogen chloride gas. The chemical reaction that occurred is as follows:\({\rm{Zn}}\,{\rm{ + }}\,{\rm{2HCl}}\, \to \,{\rm{ZnC}}{{\rm{l}}_{\rm{2}}}\,{\rm{ + }}\,{{\rm{H}}_2}\)
Q.3. What is the formula zinc chloride?
Ans: The chemical formula of zinc chloride is\({\rm{ZnC}}{{\rm{l}}_2}\).
Q.4. Why is zinc chloride as \({\rm{ZnC}}{{\rm{l}}_2}\)?
Ans: Zinc chloride exists in four crystalline forms, each of \({\rm{Zn2}} + \)ions that are trigonal planar coordinated to four chloride ions. Therefore, zinc chloride is\({\rm{ZnC}}{{\rm{l}}_2}\).
Q.5. Is zinc chloride the same as zinc?
Ans: No, Zinc chloride is a chemical compound of zinc and chlorine. So it is different from zinc metal.
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