The chemical formula for magnesium iodide is MgI2. Magnesium has a negative 2 ionic charge, so in order for the overall charge of magnesium iodide to be zero, two iodide atoms are required.
Magnesium iodide, also referred to as magnesium diiodide, appears as a brown-black powder and is often used in the Baylis-Hillman reaction. This salt has a water solubility value of 1480 grams per liter and is incompatible with air and moisture. To avoid decomposition, this compound must be stored in tightly sealed containers and kept away from excess humidity. Magnesium iodide leads to potentially dangerous reactions when inhaled or ingested. Some of the most common symptoms of prolonged exposure to magnesium iodide include headache, skin rashes and redness.