Magnesium iodide
Encyclopedia
Magnesium iodide is the name for the chemical compound
s with the formula
s 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
.
, magnesium hydroxide
, and magnesium carbonate
by treatment with hydroiodic acid:
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
powder and then adding few drops of water
on it. Both of these reactants should be extremely dry, otherwise they'll start to reacting immediately before the water is added. This reaction is very violent and produces a large quantity of toxic purple iodine
vapor.
Usage of magnesium iodide in the Baylis-Hillman reaction tends to give (Z
)-vinyl
compounds.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
s 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
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
.
Reactions
Magnesium iodide can be prepared from magnesium oxideMagnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
, magnesium hydroxide
Magnesium hydroxide
Magnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....
, and magnesium carbonate
Magnesium carbonate
Magnesium carbonate, MgCO3, is a white solid that occurs in nature as a mineral. Several hydrated and basic forms of magnesium carbonate also exist as minerals...
by treatment with hydroiodic acid:
- MgOMagnesium oxideMagnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
+ 2 HI → MgI2 + H2OWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a... - Mg(OH)2Magnesium hydroxideMagnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....
+ 2 HI → MgI2 + 2 H2O - MgCO3Magnesium carbonateMagnesium carbonate, MgCO3, is a white solid that occurs in nature as a mineral. Several hydrated and basic forms of magnesium carbonate also exist as minerals...
+ 2 HI → MgI2 + CO2Carbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
+ H2O
Magnesium iodide is stable at high heat under a hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
atmosphere, but decomposes in air at normal temperatures, turning brown from the release of elemental 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....
. When heated in air, it decomposes completely to magnesium oxide.
Another method to prepare MgI2 is mixing powdered elemental iodine and magnesium metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
powder and then adding few drops of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
on it. Both of these reactants should be extremely dry, otherwise they'll start to reacting immediately before the water is added. This reaction is very violent and produces a large quantity of toxic purple 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....
vapor.
Usage of magnesium iodide in the Baylis-Hillman reaction tends to give (Z
E-Z notation
E-Z notation, or the E-Z convention, is the IUPAC preferred method of describing the stereochemistry of double bonds in organic chemistry...
)-vinyl
Vinyl
A vinyl compound is any organic compound that contains a vinyl group ,which are derivatives of ethene, CH2=CH2, with one hydrogen atom replaced with some other group...
compounds.