Chemistry Formulas

Magnesium Iodide Formula

Magnesium Iodide

Magnesium Iodide Formula, we also know it by the name diiodomagnesium formula. It is an inorganic salt which we can easily find in seawater. In addition, it is a chemical that has numerous hydrates that are usually ionic halides that are highly soluble in water.

Magnesium Iodide Formula and Structure

The chemical and molecular formula of magnesium iodide is \( MgI_{2} \). Furthermore, I exists in various forms such as \( MgI_{2} \) (anhydrous), \( MgI_{2} \cdot 6 H_{2}O \) (hexahydrate), \( MgI_{2} \cdot 8 H_{2}O \) (octahydrate).

The molar mass of each form is: anhydrous magnesium iodide is 278.1139 g/mol, hexahydrates magnesium iodide is 386.2005 g/mol, and 422.236 g/mol for ocathydrate form of magnesium iodide. Structurally, the magnesium cation \( Mg^{2+} \) react with iodine anion \( I^{2+} \).

It exists in an anhydrous form that has a hexagonal crystal structure, a monoclinic structure for a hexahydrate form and an orthorhombic structure for octahydarte form.

Magnesium Iodide Formula

Occurrence of Magnesium Iodide

In nature, it occurs in sea salt and is a common inorganic salt. Generally, it is immediately available in most volumes, nanopowder, submicron, and high purity. Scientists prepare them in laboratories.

Preparation of Magnesium Iodide

We can prepare magnesium iodide from magnesium oxide and magnesium carbonate by treatment with hydroiodic acid. The reactions are:

\( MgO + HI \rightarrow MgI_{2} +H_{2}O \)

\( MgCO_{3} + 2 HI \rightarrow MgI_{2} + CO_{2} + H_{2}O \)

Reactions of Magnesium Iodide

At high heat under the hydrogen atmosphere it is stable. However, it decomposes in the air at normal temperature or room temperature by turning brown from the release of elemental iodine. Moreover, when we heat it in air, it completely decomposes off and from magnesium oxide.

An alternative method to prepare \( MgI_{2} \) is by mixing powdered elemental iodine and magnesium metal. to obtain anhydrous magnesium iodide \( MgI_{2} \) but this reaction needs to be conducted in a strictly anhydrous atmosphere for which we can use dry-diethyl ether as a solvent.

Properties of Magnesium Iodide

It appears as a white crystalline solid that does not have any odor. The density of its different form are: as an anhydrous solid its density is \( 4.43 g/cm^{3} \), density of hexahydrate solid is \( 2.353 g/cm^{3} \), and the density of octahydrate solid is \( 2.098 g/cm^{3} \).

Moreover, it is soluble in ether, ammonia, and alcohol. In water, it is highly soluble. Its heat capacity is 74 J/mol K. Although it is stable but under moisture and air it reacts. Its melting point is \( 637^{o} C \) and above this temperature, it decomposes.

Uses of Magnesium Iodide

Generally, we use it in internal medicine. Also, it has few commercial uses, still, we can use it to prepare compounds for organic synthesis.

Health and Safety Hazards of Magnesium Iodide

It is slightly hazardous if comes in contact with the skin and causes irritation in the eyes. Also, causes irritation if ingested or inhaled. However, the substance is toxic to the thyroid as it has iodine in it. Moreover, repeated and prolonged exposure to it can cause serious damage to organs.

Its ingestion can cause vomiting and breathing problems in some peoples. Long exposure to the eyes can cause blindness. Although it is nonflammable but can react with moisture to form magnesium hydroxide.

Solved Example for You

Question: Mention a method to prepare magnesium iodide?

Solution: We can prepare magnesium iodide by the reactions of magnesium hydroxide with hydroiodic acid:

\( Mg(OH)_{2} + 2 HI \rightarrow MgI_{2} + 2 H_{2}O \)

Explanation: When magnesium hydroxide reacts with hydroiodic acid it forms magnesium iodide and water.

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