Formula MgI2 Melting point 637 °C Density 4.43 g/cm³ | Molar mass 278.1139 g/mol Boiling point 1,014 °C Appearance white crystalline solid | |
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Magnesium iodide is the name for the chemical compounds with the formulas MgI2 and its various hydrates MgI2(H2O)x. These salts are typical ionic halides, being highly soluble in water.
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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 hydroxide, and magnesium carbonate by treatment with hydroiodic acid:
MgO + 2 HI → MgI2 + H2OMg(OH)2 + 2 HI → MgI2 + 2 H2OMgCO3 + 2 HI → MgI2 + CO2 + H2OReactions
Magnesium iodide is stable at high heat under a hydrogen 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. In order to obtain anhydrous MgI2 the reaction should be conduct in a strictly anhydrous atmosphere and dry-diethyl ether can be used as a solvent.
Usage of magnesium iodide in the Baylis-Hillman reaction tends to give (Z)-vinyl compounds.