White fine powder. Odorless. Due to different preparation methods, there are light and heavy. Activated magnesium oxide is highly refractive in the visible and near-ultraviolet range. When exposed to air, it is easy to absorb moisture and carbon dioxide and gradually become basic magnesium carbonate. Light weight is faster than heavy weight. It combines with water to form magnesium hydroxide, which is slightly alkaline reaction. However, it is easily soluble in dilute acid and very slightly soluble in pure water, and its solubility is increased due to the presence of carbon dioxide. Insoluble in ethanol. Relative density (d254) 3.58. Melting point 2852 ℃. Boiling point 3600 ℃.

White or light yellow powder, odorless, tasteless, insoluble in water or ethanol, slightly soluble in ethylene glycol, melting point 2852 ℃, boiling point 3600 ℃, magnesium oxide has high refractory insulation properties. It can be transformed into crystals after high temperature burning above 1000 ℃, and when it rises above 1500 ℃, it will become dead-burned magnesia (that is, the so-called magnesia) or sintered magnesia.

Chemical properties: Magnesium oxide is an alkaline oxide, with the general properties of alkaline oxides, and belongs to a cementitious material

When exposed to the air, it is easy to absorb moisture and carbon dioxide and gradually become basic magnesium carbonate. The light product is faster than the heavy product. It combines with water to form magnesium hydroxide, which is slightly alkaline. The pH of the saturated aqueous solution is 10.3. Soluble in acid and ammonium salts, insoluble in water, and its solution is alkaline. Insoluble in ethanol.