Compounds strontium

Selective Reduction. In aqueous solution, europium(III) [22541 -18-0] reduction to europium(II) [16910-54-6] is carried out by treatment with amalgams or zinc, or by continuous electrolytic reduction. Photochemical reduction has also been proposed. When reduced to the divalent state, europium exhibits chemical properties similar to the alkaline-earth elements and can be selectively precipitated as a sulfate, for example. This process is highly selective and allows production of high purity europium fromlow europium content solutions (see Calcium compounds Strontiumand strontium compounds). 

In spite of widespread usage of these compounds, the stmctures of only the calcium, barium, and strontium compounds are reasonably weU-estabhshed. The materials are generally made by trituratiag the oxides, or hydroxides, with aqueous hydrogen peroxide and dryiag the soHd products. The commercial products are typically mixtures of the peroxides with varyiag amounts of hydroxides, oxides, carbonates, hydrates, and peroxohydrates. 

Uses. The main appHcation for strontium is in the form of strontium compounds. The carbonate, used in cathode ray tubes (CRTs) for color televisions and color computer monitors, is used both in the manufacturing of the glass envelope of the CRT and in the phosphors which give the color. 

Strontium has a valence of +2 and forms compounds that resemble the compounds of the other alkaline-earth metals (see Barium compounds Calcium compounds). Although many strontium compounds are known, there are only a few that have commercial importance and, of these, strontium carbonate [1633-05-2] SrCO, and strontium nitrate [10042-76-9], Sr(N03)2, are made in the largest quantities. The mineral celestite [7759-02-6], SrSO, is the raw material from which the carbonate or the nitrate is made. 

Strontium carbonate is the principal strontium compound consumed. Other commercial compounds include strontium nitrate and strontium hydrate. The latter is available in an anhydrous form or as the dihydrate or octahydrate form and is called strontium hydrate. 

There are two main processes for conversion of celestite, ie, strontium sulfate, to strontium carbonate. The principal process is the black ash process. Strontium nitrate is produced by dissolving celestite in nitric acid and purifying it. Most other strontium compounds are produced from strontium nitrate. To service this market, NOAH Technologies Corporation (San Antonio, Texas) has estabUshed a plant in Mexico to manufacture most commercial- and reagent-grade strontium compounds except strontium carbonate. 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Barium is a member of the aLkaline-earth group of elements in Group 2 (IIA) of the period table. Calcium [7440-70-2], Ca, strontium [7440-24-6], Sr, and barium form a closely aUied series in which the chemical and physical properties of the elements and thek compounds vary systematically with increa sing size, the ionic and electropositive nature being greatest for barium (see Calcium AND CALCIUM ALLOYS Calcium compounds Strontium and STRONTIUM compounds). As size increases, hydration tendencies of the crystalline salts increase solubiUties of sulfates, nitrates, chlorides, etc, decrease (except duorides) solubiUties of haUdes in ethanol decrease thermal stabiUties of carbonates, nitrates, and peroxides increase and the rates of reaction of the metals with hydrogen increase. 

Numerous other specialty cements composed of various magnesium, barium, and strontium compounds as siUcates, aluminates, and phosphates, as well as others, are also produced (85). 

Crimson Strontium compounds (masked by barium), appear violet through cobalt glass, yellowish through green glass. 

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... 

Strontium oxide is used for preparing other strontium compounds. 

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