Chemical formula Mg (OH) 2, formula weight 58.32. White, amorphous powder. Insoluble in water, soluble in acid and ammonium salt solution. Saturated aqueous solution concentration was 1.9 mg / L (18 ℃), alkaline. Loss of water was heated to 350 ℃ generating magnesium oxide. Using the kit, but also for the pharmaceutical industry. Water reaction with available magnesium hydroxide. Used as a flame retardant, the reference amount of 40 to 200 copies. Also used as a synthetic magnesium phenol and formaldehyde phenolic resin catalyst. Magnesium hydroxide is widely used as PE, PP, PVC, ABS, PS, HIPS, PA, PBT, flame retardant and excellent filler unsaturated polyester, epoxy, rubber and other polymer materials. In electronics, unsaturated polyester and paint, coatings and other polymer materials, especially mine duct coated cloth, PVC whole core conveyor belt, flame retardant plastic sheet, tarpaulin, PVC wire and cable materials, mining cable sheathing, flame retardant cable accessories, smoke and anti-static fields, can replace aluminum hydroxide, with excellent flame retardant effect. For the manufacture of magnesium, magnesium oxide activity, acid waste neutralizer, color TV picture tube cone glass coatings industry. In medicine used as an antacid gentle laxatives, can also be used, such as sugar and magnesium; magnesium hydroxide is plastic, rubber excellent flame retardant. Environmental aspects as flue gas desulfurization agent, can replace caustic soda and lime as acid waste neutralizer. Also used as oil additives, corrosion and desulfurization play.