Magnesium sulfite is an ionic compound composed of one positively charged magnesium ion and one negatively charged sulfite ion. The chemical formula of magnesium sulfite is MgSO3.
The magnesium ion in magnesium sulfite has a positive charge of 2. The sulfite ion consists of one sulphur atom covalently bonded to three oxygen atoms, two of which carry a charge of -1, which gives an overall charge of -2 to the sulfite ion. An ionic bond exists between the positively charged magnesium ion and the negatively charged sulfite ion. Magnesium sulfite commonly exists in a hydrated form, in which it weakly bonds with water molecules.