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Magnesium hydroxide, chemical formula Mg(OH)2, formula 58.32. White amorphous powder. The name is caustic soda, light burned magnesia, etc., the suspension of magnesium hydroxide in water is called magnesium hydroxide emulsion, referred to as magnesium milk, the English name is Magnesium hydroxide. Magnesium hydroxide is a colorless hexagonal column crystal or white powder, hardly soluble in water and alcohol, soluble in dilute acid and ammonium salt solution, and the aqueous solution is weakly alkaline. The solubility in water is small, but the water-soluble fraction is completely ionized. The concentration of the saturated aqueous solution was 1.9 mg/liter (18 ° C). Heating to 350 ° C loses water to form magnesium oxide. Natural mineral brucite of magnesium hydroxide. Can be used in sugar and magnesium oxide. Because magnesium hydroxide is abundant in nature and its chemical properties are similar to aluminum, usesrs have begun to use magnesium hydroxide instead of aluminum chloride for fragrance products. Used as an analytical reagent and also used in the pharmaceutical industry.

Physical and chemical properties

Appearance and Properties: odorless white powder, density: 2.36g/cm3, melting point: 350oC (Decomposes), boiling point: 100oC at 760mmHg, flash point: will not burn, stability: Stable.

Chemical properties

Magnesium hydroxide is a medium-strong base (the solubility of magnesium hydroxide is very small, the solution is very alkaline, sometimes treated as a weak base), and heated to 623K (350 ° C), ie dehydration decomposition: Mg(OH) 2 →MgO+H2O, easy Soluble in acid or ammonium salt solution. As with magnesium oxide, it absorbs carbon dioxide in the air and gradually forms a basic carbonate having a composition of 5MgO?4CO2?xH2O. Decomposes to magnesium oxide and water at temperatures above 350 ° C, but only at temperatures above 1800 ° C can be completely dehydrated.