Magnesium iodide is the name for the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

s with the formulas MgI₂ and its various hydrates MgI₂(H₂O)_x. These salts are typical ionic halides, being highly soluble in water.

Uses

Magnesium iodide has few commercial uses, but can be used to prepare compounds for organic synthesis.

Preparation

Magnesium iodide can be prepared from

magnesium oxide Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...

magnesium hydroxide Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (). Magnesium hydroxide is a common component of antacids, such as milk ...

, and magnesium carbonate by treatment with

hydroiodic acid Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI. Reactions Hy ...

: :

MgO Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...

+ 2 HI → MgI₂ + H₂O : Mg(OH)₂ + 2 HI → MgI₂ + 2 H₂O : MgCO₃ + 2 HI → MgI₂ + CO₂ + H₂O

Reactions

Magnesium iodide is stable at high heat under a

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atmosphere, but decomposes in air at normal temperatures, turning brown from the release of elemental iodine. When heated in air, it decomposes completely to magnesium oxide. Another method to prepare MgI₂ is mixing powdered elemental iodine and magnesium

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

. In order to obtain anhydrous MgI₂, the reaction should be conducted in a strictly anhydrous atmosphere; dry-diethyl ether can be used as a solvent. Usage of magnesium iodide in the Baylis-Hillman reaction tends to give ( Z)-

vinyl Vinyl may refer to: Chemistry * Polyvinyl chloride (PVC), a particular vinyl polymer * Vinyl cation, a type of carbocation * Vinyl group, a broad class of organic molecules in chemistry * Vinyl polymer, a group of polymers derived from vinyl ...

compounds.

References

{{Iodides Iodides Magnesium compounds Alkaline earth metal halides Deliquescent substances