Strontium oxide melting point

Strontium carbonate is a colorless or white crystalline soHd having a rhombic stmcture below 926°C and a hexagonal stmcture above this temperature. It has a specific gravity of 3.70, a melting point of 1497°C at 6 MPa (60 atm), and it decomposes to the oxide on heating at 1340°C. It is insoluble in water but reacts with acids, and is soluble in solutions of ammonium salts. 

Strontium Oxide, Hydroxide, and Peroxide. Strontium oxide, SrO, is a white powder that has a specific gravity of 4.7 and a melting point of 2430°C. It is made by heating strontium carbonate with carbon in an electric furnace, or by heating celestite with carbon and treating the sulfide formed with caustic soda and then calcining the product (10). It reacts with water to form strontium hydroxide [18480-07-4] and is used as the source of strontium peroxide [1314-18-7],... 

Strontium metal is not found in its elemental state in nature. Its salts and oxide compounds constitute only 0.025% of the Earths crust. Strontium is found in Mexico and Spain in the mineral ores of strontianite (SrCO ) and celestite (SrSO ). As these ores are treated with hydrochloric acid (HCl), they produce strontium chloride (SrCy that is then used, along with potassium chloride (KCl), to form a eutectic mixture to reduce the melting point of the SrCl, as a molten electrolyte in a graphite dish-shaped electrolysis apparatus. This process produces Sr cations collected at the cathode, where they acquire electrons to form strontium metal. At the same time, Cl anions give up electrons at the anode and are released as chlorine gas Cl T. 

The metal is prepared by electrolysis of a fused salt mixture containing strontium chloride and potassium chloride (to decrease the melting point). An alternative method is reduction of strontium oxide by aluminum at so high a temperature that the strontium metal is distilled off and can be condensed (the boiling point for strontium is 1382°q. 

The synthesis of the title compositions has been selected as representative of compounds that can readily be prepared by the flux-reaction technique. In this technique, a halide melt serves both as a flux and as a constituent component of the basic reaction. The procedure has been described in the literature1 and has served for the preparation of a variety of ternary oxides, usually in the form of small, well-defined, single crystals. The halide phosphates and vanadates of strontium represent the apatite and spodiosite structures, both interesting compositions from a biochemical and solid-state point of view. 

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