Magnesium oxide (MgO) is an ionic substance that crystallises and breaks into 100 and 111 planes in the rock-salt structure. In nature, it is found as periclase or β-magnesia. It is considered that magnesium oxide is ionic. This implies that bonds are formed between atoms that hold magnesium and oxygen together.
Reaction with oxygen present in the air to form Magnesium Oxide as the magnesium metal burns. A compound is a substance in which atoms of various elements are bound to each other. Oxygen and magnesium interact to form this complex in a chemical reaction. An inorganic substance like the mineral periclase that occurs in nature. It easily combines with water to form magnesium hydroxide in aqueous media. It is used as a moderate laxative and an antacid, and has numerous non-medicinal applications.