Magnesium Carbonate

magnesium carbonate [mag′nē·zē·əm ′kär·bə‚nāt]

(inorganic chemistry)

MgCO₃A water-insoluble, white powder, decomposing at about 350°C; used as a refractory material.

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magnesia insulation

Magnesium carbonate hydroxide, with or without admixture of fiber reinforcement or other materials; a good thermal insulator because of the great number of closed air cells it contains; molded into rigid boards, blocks, or shapes conforming to piping.

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Magnesium Carbonate 

MgCO₃, a salt; colorless crystals. Density, 3.037 g/cm³. The decomposition of magnesium carbonate into MgO and CO₂ is partial at 500°C and complete at 650°C Its solubility in water is low (22 mg/l at 25°C) and decreases with increasing temperature. Upon saturation of an

aqueous suspension of MgCO₃ with CO₂, the MgCO₃ dissolves because of the formation of the hydrocarbonate Mg(HCO₃)₂. Basic magnesium carbonates are extracted from aqueous solutions in the absence of excess CO₂. Magnesium carbonate interacts with metal carbonates to form double salts, an example of which is the natural mineral dolomite, MgCO₃,CaCO₃. Magnesium carbonate is widespread in nature in the form of the mineral magnesite. Basic magnesium carbonate, 3MgCO₃,Mg(OH)₂,3H₂O, is used as a filler in rubber mixes, in the manufacture of thermal-insulation materials, and in medicine (as a tooth-powder ingredient and internally to counteract increased acidity).