Classification: light weight Magnesium Oxide and heavy Magnesium Oxide two kinds. The light weight is loose and it is a white amorphous powder. Odorless and tasteless and nontoxic. The density is 3.58g/cm3. It is difficult to dissolve in pure water and organic solvents, and the solubility in water increases with the presence of carbon dioxide. It can be dissolved in acid and ammonium salt solution. It is transformed into a crystalline body by high temperature burning. Magnesium carbonate is produced in the presence of carbon dioxide in the air. Heavy and compact, white or beige powder. Easy to combine with water, easy to absorb moisture and carbon dioxide in the air. Mixed with magnesium chloride solution is easy to gel and harden.