5677. Magnesium Oxide

Nomenclature

CAS number: 1309-48-4
Magnesium oxide (MgO); magnesia; calcined magnesia; magnesia usta; Magcal; Maglite (Marine Magnesium).
MgO; mol wt 40.30.
Mg 60.31%, O 39.70%.

Description and references

Occurs in nature as the mineral periclase. Commercial prepn from magnesite ores: Adams, US 3320029 (1967 to Northwest Magnesite).

Properties

White, very fine, odorless powder. Available in a very bulky form termed “Light” or in a dense form termed “Heavy”. Takes up CO2 and H2O from the air, the light form more readily than the heavy. mp 2800°. Highly reflective in visible and near uv region. Combines with water to form magnesium hydroxide. Very slightly sol in pure water, soly increased by CO2; sol in dil acids; insol in alcohol. Imparts a slight alkaline reaction to water. pH of satd aq soln 10.3. Keep well closed.

Caution

Potential symptoms of overexposure to fumes are irritation of eyes and nose; metal fume fever (coughing, chest pain and flu-like fever). See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 188.

Use

Manuf refractory crucibles, fire bricks, magnesia cements and boiler scale compounds, “powdered” oils, casein glue. Reflector in optical instruments; white color standard. Insulator at low temp. Absorbant for colorants prior to determn. Prepn of Eschka's reagent.

Therapeutic Category

Antacid.

Therapeutic Category (Veterinary)

Antacid, laxative, in hypomagnesemia.

Keywords

Antacid