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Magnesium iodide

Magnesium iodide

General
Systematic name	Magnesium iodide
Molecular formula	MgI₂ (anhydrous) MgI₂.6H₂O (hexahydrate) MgI₂.8H₂O (octahydrate)
Molar mass	278.114 g/mol (anhydrous) 386.2005 g/mol (hexahydrate) 422.236 g/mol (octahydrate)
Appearance	white crystalline solid
CAS number	10377-58-9 (anhydrous) 75535-11-4 (hexahydrate) 7790-31-0 (octahydrate)
Properties
Density and phase	4.43 g/cm³ (anhydrous solid) 2.353 g/cm³ (hexahydrate solid) 2.098 g/cm³ (octahydrate solid)
Solubility in water	54.7 g/100 cm³ (anhydrous, 0 °C) 81 g/100 cm³ (octahydrate, 20 °C)
Melting point	637 °C (anhydrous, decomposes) 41 °C (octahydrate, decomposes)
Structure
Crystal structure	Hexagonal (anhydrous) Monoclinic (hexahydrate) Orthorhombic (octahydrate)
Hydrates	Hexahydrate, Octahydrate^[1]
Hazards
R/S statement	R: R36 R38 R42 R43 R61 S: S22 S36/37/39 S45 S53^[2]
Supplementary data page
Related compounds
Other anions	Magnesium fluoride Magnesium bromide Magnesium chloride
Other cations	beryllium iodide calcium iodide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

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

Additional recommended knowledge

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Essential Laboratory Skills Guide

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Reactions

Magnesium iodide can be prepared from magnesium oxide, magnesium hydroxide, and magnesium carbonate by treatment with hydroiodic acid^[3]:

MgO + 2 HI → MgI₂ + H₂O

Mg(OH)₂ + 2 HI → MgI₂ + 2 H₂O

MgCO₃ + 2 HI → MgI₂ + CO₂ + H₂O

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 ^[4].

Usage of magnesium iodide in the Baylis-Hillman reaction tends to give (Z)-vinyl compounds ^[5].

References

^ Perry, Dale L. & Phillips, Sidney L., , CRC Press, pp. 240, ISBN 0849386713, . Retrieved on 2007-12-09
^ http://ptcl.chem.ox.ac.uk/MSDS/MA/magnesium_iodide.html
^ Patnaik, Pradyot, , McGraw-Hill Professional, pp. 527-528, ISBN 0070494398, . Retrieved on 2007-12-09
^ N. T. M., Wilsmore (1891). "Note on Magnesium Iodide". James Hector Report of the Third Meeting of the Australasian Association for the Advancement of Science: 116, Sydney: The Association. Retrieved on 2007-12-09.
^ Tietze, Lutz-Friedjan; Brasche, Gordon & Gericke, Kersten, , Wiley-VCH, pp. 59, ISBN 3527290605, . Retrieved on 2007-12-09

Category: Iodides

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Magnesium_iodide". A list of authors is available in Wikipedia.