MAGNESIUM - MgProperties of Magnesium: The silver-white, relatively soft, ductile, malleable metal. On air covered with an oxide film. Passivated in cold water, concentrated sulfuric acid and hydrofluoric acid. Does not react with alkalis. A strong reducing agent, reacts with hot water, diluted acids, nonmetals. Transferred to solution by ammonium salts.
Methods for preparation of Magnesium: MgO + C(coke) = Mg + CO (over 2000°C). MgO + Ca = CaO + Mg (1300°C). Mg3N2 = 3Mg + N2 ( 700-1500°C). MgCl2(melt) → Electrolysis → Mg(cathode) + Cl2↑(anode). Сhemical reactions with Magnesium: Mg + 2H2O(hot) = Mg(OH)2↓ + H2↑. Mg + 2HCl(diluted) = MgCl2 + H2↑. 4Mg + 10HNO3(diluted) = 4Mg(NO3)2 + 2N2O↑ + 5H2O. Mg + 2NH4Cl(conc., hot) = MgCl2 + 2NH3↑ + H2↑. Mg + H2 = MgH2 (175°C, pressure, catalyst MgI2). 2Mg + O2 = 2MgO (600-650°C, combustion on air), 3Mg + N2 = Mg3N2 (780-800°C, combustion on air). Mg + Cl2(moist) = MgCl2 (normal temp.). Mg + H2S = MgS + H2 (500°C). 3Mg + 2NH3 = Mg3N2 + 3H2 (600-850°C). Mg + 2N2O4 = Mg(NO3)2↓ + 2NO (150°C, vaccum, in ethyl acetate). 4Mg + SiO2 = Mg2Si + MgO (below 800°C, in the atmosphere of H2), 2Mg + SiO2 = Si + 2MgO (1000°C). |
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DNA is flame retardant.