Strontium oxides

Strontium is found chiefly as celestite and strontianite. The metal can be prepared by electrolysis of the fused chloride mixed with potassium chloride, or is made by reducing strontium oxide with aluminum in a vacuum at a temperature at which strontium distills off. Three allotropic forms of the metal exist, with transition points at 235 and 540oC. 

Strontium Peroxide. Commercial strontium peroxide contains about 85% Sr02 and 10% active oxygen. It can be made by heating strontium oxide ia the preseace of oxygea gas uader 20 MPa (200 atm) pressure, or by reactiag a soluble stroatium salt with hydrogea peroxide. The only substantial appHcation for this compound is ia pyrotechnics (qv). Strontium peroxide [1314-18-7] produces a red color ia flames. 

Occurrence. The principal strontium mineral is celestite, naturally occurring strontium sulfate. Celestite and celestine [7759-02-6] both describe this mineral. However, celestite is the form most widely used in Knglish-speaking countries. Celestite has a theoretical strontium oxide content of 56.4 wt %, a hardness of 3—3.5 on Mohs scale, and a specific gravity of 3.96. It is usually white or bluish white and has an orthorhombic crystal form. 

Strontianite is the naturally occurring form of strontium carbonate. It has a theoretical strontium oxide content of 70.2%, but no economically workable deposits are known. There are some naturally occurring strontium—barium and strontium—calcium isomorphs, but none has economic importance. 

Production. MetaUic strontium was first successfully produced by the electrolysis of fused strontium chloride. Although many attempts were made to develop this process, the deposited metal has a tendency to migrate into the fused electrolyte and the method was not satisfactory. A more effective early method was that described in Reference r5. Strontium oxide is reduced thermally with aluminum according to the following reaction ... 

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 peroxide, Sr02, is a white powder with a specific gravity of 4.56 that decomposes in water. It is made by the reaction of hydrogen peroxide with strontium oxide and is used primarily in pyrotechnics and medicines. 

The anode material in SOF(7s is a cermet (rnetal/cerarnic composite material) of 30 to 40 percent nickel in zirconia, and the cathode is lanthanum rnanganite doped with calcium oxide or strontium oxide. Both of these materials are porous and mixed ionic/electronic conductors. The bipolar separator typically is doped lanthanum chromite, but a metal can be used in cells operating below 1073 K (1472°F). The bipolar plate materials are dense and electronically conductive. 

In 1817 Dobereiner found that if certain elements were combined with oxygen in binary compounds, a numerical relationship could be discerned among the equivalent weights of these compounds. Thus when oxides of calcium, strontium, and barium were considered, the equivalent weight of strontium oxide was approximately the mean of those of calcium oxide and barium oxide. The three elements in question, strontium, calcium, and barium were said to form a triad. 

C04-0102. Write the balanced redox reactions for the formation of each of the following oxides from the reaction of molecular oxygen with pure metal (a) strontium oxide (b) chromium(III) oxide (c) tin(IV) oxide. 

As with calcium and strontium oxides, barium oxide reacts very exothermically with water, forming hydrogen.The heat which is released is such that it can, like... 

Strontium compounds, 23 319-324 estimated distribution of, 23 3201 world production of, 23 319-320 Strontium cyanide, 8 197 Strontium ferrate (1 1), 5 598 Strontium fluoride, 23 323 Strontium fluoroborate tetrahydrate, 4 153 Strontium halides, 23 323 Strontium hexaferrite, 23 323 Strontium hydride, 13 613 Strontium hydroxide, 23 324 Strontium iodide, 23 323 Strontium-lead alloys, 14 779 Strontium minerals, 23 320 producers of, 23 319 Strontium nitrate, 23 319, 321, 323 Strontium oxide, 23 318, 324 Strontium peroxide, 18 396, 23 324 Strontium-silicon alloy, 22 520 Strontium sulfate, 23 322, 324 Strontium sulfide, 23 322 Strontium titanate... 

STANNIC BROMIDE STANNOUS CHLORIDE STANNIC CHLORIDE STANNIC HYDRIDE STANNIC IODIDE STRONTIUM STRONTIUM OXIDE TANTALUM TECNNETIUM TELLURIUM... 

STRONTIUM OXIDE 2848.9447 -4.0303E+05 -8.7252E+02 1.3051E-01 -7.7456E... 

Two other methods of producing strontium are by thermal reduction of strontium oxide and by the distillation of strontium in a vacuum. 

During combustion, strontium nitrate and strontium carbonate decompose to give strontium oxide whose spectrum is seen as a pinkish flame due to the positions of the emission bands and to the difficulty in obtaining a high concentration of strontium oxide vapour in the flame. This difficulty is due to the high sublimation temperature of the oxide which is in excess of 2500 °C. 

Strontium metal also can be prepared by thermal reduction of its oxide with aluminum. Strontium oxide-aluminum mixture is heated at high temperature in vacuum. Strontium is collected by distillation in vacuum. Strontium also is obtained by reduction of its amalgam, hydride, and other salts. The amalgam is heated and the mercury is separated by distillation. If hydride is used, it is heated at 1,000°C in vacuum for decomposition and removal of hydrogen. Such thermal reductions yield high—purity metal. 

Strontium is a reactive metal, similar to calcium. Exposure to air forms strontium oxide, SrO. In finely-divided form, the metal is pyrophoric. It... 

Strontium chloride is prepared by reacting strontium oxide, hydroxide, or carbonate in hydrochloric acid ... 

Strontium hydroxide is prepared by treating strontium oxide with water ... 

The tetrahydrate constitutes colorless monoclinic crystals density 2.20 g/cm3 loses all water of crystallization at 100°C converts to strontium oxide, SrO at 1,100°C very soluble in water, 60.4g/100 mL at 0°C, 206 g/100 mL at 100°C soluble in liquid ammonia very slightly soluble in ethanol and acetone. 

Strontium oxide is used for preparing other strontium compounds. 

Strontium oxide is prepared by thermal decomposition of strontium carbonate, hydroxide, or nitrate ... 

Strontium sulfate occurring in nature as celestite is mined from its natural deposits. Also, the sulfate can be made by reacting strontium oxide, hydroxide, or carbonate with dilute hydrochloric acid ... 

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