Rapid strontium

The uptake and incorporation of other elements, magnesium or strontium, in the calcite have been investigated and shown the bioavailability of these elements. In modem ocean waters, the content and range of magnesium in biotic and abiotic deposited minerals were virtually identical in studies by Carpenter and Lohmann (1992). However, there was a more rapid strontium uptake in the calcium-rich biomineral. The composition of the calcium carbonate mineral deposited is a function of kinetics and related to the metabolism of the organism. 

Strontium is softer than calcium and decomposes in water more vigorously. It does not absorb nitrogen below 380oC. It should be kept under kerosene to prevent oxidation. Freshly cut strontium has a silvery appearance, but rapidly turns a yellowish color with the formation of the oxide. The finely divided metal ignites spontaneously in air. Volatile strontium salts impart a beautiful crimson color to flames, and these salts are used in pyrotechnics and in the production of flares. Natural strontium is a mixture of four stable isotopes. 

Strontium-89 chloride is a calcium analogue that rapidly clears from the blood and is taken up into bone mineral, particularly in areas of active osteogenesis, as weU as primary bone tumors and metastases. It is used for reHef of bone pain in patients having painful skeleton bone metastases. It is suppHed in an injectable solution. 

Historically, strontium metal was produced only in very small quantities. Rapid growth of metal production occurred during the late 1980s, however, owing to use as a eutectic modifier in aluminum—silicon casting alloys. The addition of strontium changes the microstmcture of the alloy so that the siUcon is present as a fibrous stmcture, rather than as hard acicular particles. This results in improved ductility and strength in cast aluminum automotive parts such as wheels, intake manifolds, and cylinder heads. 

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. 

Strontium chloride (6H2O) [1025-70-4] M 266.6, m 61 (rapid heating), 114-lS0 (loses 5H2O), 868 (anhydr). Crystd from warm water (0.5mL/g) by cooling to 0°. 

To be effective, there must be a certain minimum concentration of inhibitor at the interface to be protected. Therefore, there must be sufficient inhibitor in the primer, and these inhibitors need to be soluble enough in water to enable transport of inhibitor to the oxide surface as water permeates the adhesive joint. However, too high of a solubility will rapidly deplete the primer layer of inhibitor resulting in a loss of protection. One of the fortuitous properties of zinc and strontium chromates is the limited solubility of these compounds in water (about 1.2 g/1 at 15°C [33]). 

Sugden and Schofield (33) suggest that this reaction (with a rate constant 40-8 cm.3 molecule-1 sec.-1) can account for the boost in ionization of sodium observed when strontium salts are supplied to flames containing sodium. There is evidence (24, 33, 36) which strongly suggests that equilibrium ionization of strontium in flames is rapidly established via... 

D. 2,3-Diamino pyridine (Note 12). In an apparatus for catalytic hydrogenation (Note 13) 56.4 g. (0.3 mole) of 2,3-diamino-5-bromopyridine suspended in 300 ml. of 4% sodium hydroxide solution is shaken with hydrogen in the presence of 1.0 g. of 5% palladized strontium carbonate (Note 14). When absorption of hydrogen is completed, the catalyst is removed by filtration, and, after saturation with potassium carbonate (about 330 g. is required), the resulting slushy mixture is extracted continuously with ether until all the precipitate completely disappears (usually about 18 hours, but this depends on the efficiency of the extraction apparatus). The ether is removed by distillation, and the residue of crude 2,3-diaminopyridine is recrystallized from benzene (about 600 ml. is required) using 3 g. of activated charcoal and filtering rapidly through a preheated Buchner funnel. The yield of 2,3-diaminopyridine, obtained as colorless needles, m.p. 115-116°, pKa 6.84, is 25.5-28.0 g. (78-86%) (Note 15). 

Strontium-90, a radioactive strontium isotope with a half-hfe of 29 years, is a dangerous fallout source of radiation from atmospheric nuclear bombs. If a person is exposed to it, it will rapidly accumulate in bone tissue and interfere with the production of new red blood cells... 

Figure 6.10 ICP mass spectrum of strontium, yttrium and zirconium without collision gas (a) and using collision gas (b) to suppress interfering ions. ( . C. Eiden, C. /. Barinaga and D. W. Koppenaal, Rapid Comm. Mass Spectrom. 11, 27 (1997). Reproduced by permission of John Wiley Sons, Ltd.)...

The explosive properties of sodium, calcium, strontium and barium azides have been investigated at the Chemisch-Technische Reichsanstalt [135]. These azides differ markedly from lead, silver and cupric azides in that they show none of the properties of primary explosives. All three may be ignited by a spark, a glowing wire or the flame of blackpowder. Calcium azide bums most rapidly and has distinctly marked explosive properties. Larger quantities of it may explode when ignited in a closed tin, while strontium and barium merely bum violently. Calcium azide detonates under the influence of a detonating cap. The sodium azide does not decompose in these conditions. The other azides show weak decomposition under the influence of a standard (No. 3) detonator. Their most important properties are tabulated below. 

Strontium Arsenide, Sr3As2, may be prepared by reduction of strontium arsenate. This is best accomplished by rapidly heating with carbon 10 to 1500° to 1600° C. If the heating is slow, reduction begins at about 800° C-. yielding first the arsenite, arsenic then being lost and strontium oxide formed. Calcium arsenate behaves similarly (p. 60). Strontium arsenide forms reddish-brown crystals, transparent in thin... 

Strontium is a silver-white metal, soft as lead, malleable, ductile, oxidizes rapidly on exposure to air, burns when heated in air emitting a biilliant light and forming oxide and nitiide. reacts with H2O yielding strontium hydroxide and hydrogen gas. Discovered by Hope and by Klaproth in 1793. and isolated by Davy in 1808. 

Conditions for Rapid Photocorrosion at Strontium Titanate Photoanodes... 

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