Zinc iodide is a chemical compound of zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 and iodine

Iodine

Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

, ZnI₂. The anhydrous form is white and readily absorbs water from the atmosphere. It can be prepared by the direct reaction of zinc and iodine in refluxing ether

Ether

Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...

. or by reacting zinc with iodine in aqueous solution:

Zn + I₂→ ZnI₂

At 1150 °C, zinc iodide vapour dissociates into zinc and iodine.

In aqueous solution the following have been detected, octahedral Zn(H₂O)₆²⁺, [ZnI(H₂O)₅]⁺ and tetrahedral ZnI₂(H₂O)₂, ZnI₃(H₂O)⁻ and ZnI₄²⁻.

The structure of crystalline ZnI₂ is unusual, and while zinc atoms are tetrahedrally coordinated, as in ZnCl₂

Zinc chloride

Zinc chloride is the name of chemical compound with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from...

, groups of four of these tetrahedra share three vertices to form “super-tetrahedra” of composition {Zn₄I₁₀}, which are linked by their vertices to form a three dimensional structure.