Strontium isolation

Special chemical treatment can isolate the nuchdes of intermediate half-life, ie, cesium-137 and strontium-90 [10098-97-2] Sr, 39 yr (15). These... 

OC-Hydroxycarboxylic Acid Complexes. Water-soluble titanium lactate complexes can be prepared by reactions of an aqueous solution of a titanium salt, such as TiCl, titanyl sulfate, or titanyl nitrate, with calcium, strontium, or barium lactate. The insoluble metal sulfate is filtered off and the filtrate neutralized using an alkaline metal hydroxide or carbonate, ammonium hydroxide, amine, or alkanolamine (78,79). Similar solutions of titanium lactate, malate, tartrate, and citrate can be produced by hydrolyzation of titanium salts, such as TiCl, in strongly (>pH 10) alkaline water isolation of the... 

The only known stable soHd neutral hypochlorites are those of lithium, calcium, strontium [14674-76-17, and barium [13477-10-6]. Calcium also forms two stable basic hypochlorites (calcium hydroxide hypochlorites) Ca(OCl)2 0.5Ca(OH)2 [62974-42-9] and Ca(OCl)2 2Ca(OH)2 [12394-14-8], Sodium hypochlorite [7681-52-9] does not have good stabiHty. Potassium hypochlorite [7778-66-7] exists only in solution. Attempts to isolate the soHd have... 

Organomagnesium derivatives have not so far been isolated [80JA994 80JOM(193)C13]. Bis[bis(trimethylsilyl)phosphonamide] with diphenylbutadi-yne and calcium or strontium in THE yields the TiyP)-coordinated species 129. Reaction of (THE)4Ba[P(SiMc3)2]2 with diphenylbutadiyne gives an ri -coordinated species 130 (98JA6722). 1-Chloro-and l-cyclopentadienyl-3,4-dimethyl-2,5-bis-(trimethylsilyl)-l-phosphacyclopenta-2,4-dienes both react with calcium to give... 

Erdal, B.R. Aguilar, R.D. Bayhurst, B.P. Daniels, W.R. Duffy, C.J. Lawrence, F.O. Maestas, S. Oliver, P.Q. Wolfsberg, K. "Sorption-Desorption Studies on Granite. I. Initial Studies of Strontium, Technetium, Cesium, Barium, Cerium, Europium, Uranium, Plutonium, and Americium", in "Proceedings of the Task 4 Waste Isolation Safety Assessment Program Second Contractor Information Meeting", Vol. II, Report PNL-SA-7352, Battelle Pacific Northwest Laboratory, 1978, pp. 7-67. 

Sm(DippForm)2(THF)2 is isomorphous with the related strontium and barium amidinates. The trivalent samarate complex [Na(THF)5][Sml2(Dipp-Form)2(THF)2] was isolated in small quantities as a colorless by-product. Dissolution of this compound in hexane led to ligand redistribution to give homoleptic Sm(DippForm)3 with concomitant precipitation of Nal and SmlsfTHFls.s. The monofluoro-bis(amidinate) SmF(DippForm)2(THF) could also be isolated from Sm(DippForm)2(THF)2. ... 

Since aldehydes are notoriously polymerizable and difficult to manipulate, the products of periodate oxidation are oftentimes further oxidized, with hypohalite, to carboxylic acids, or are reduced to the corresponding alcohols. Oxidation has been more usually employed than reduction, since acids frequently form crystalline salts and other conveniently prepared derivatives. A process of oxidation of these aldehydic products by hypo-bromite, in the presence of barium carbonate or strontium carbonate, was developed and used extensively by Hudson and his coworkers.107 110 194-199,90s Their method can best be illustrated by an example the further oxidation of the dialdehyde, VI, shown previously (see p. 16) to be obtained by the oxidation of the methyl a-D-aldohexopyranosides. The isolation of... 

It is also possible to isolate bis(carbene) complexes involving the heavier alkaline earth metals. Thus, the reaction of two equivalents of 4 (R = Me or (Bu, R = H) with calcium, strontium and barium bis(trimethylsilyl)amides [M N(SiMe3)2 2(thf)2] (M = Ca, Sr, Ba) resulted in the displacement of two thf molecules to afford the corresponding biscarbene species, 19 (19). The solubilities and stabilities of these complexes were found to decrease from calcium to barium. 

Another application is in the oxidation of vapour mixtures in a chemical vapour transport reaction, the attempt being to coat materials with a thin layer of solid electrolyte. For example, a gas phase mixture consisting of the iodides of zirconium and yttrium is oxidized to form a thin layer of yttria-stabilized zirconia on the surface of an electrode such as one of the lanthanum-strontium doped transition metal perovskites Lai Sr MO --, which can transmit oxygen as ions and electrons from an isolated volume of oxygen gas. 

Strontium - the atomic number is 38 and the chemical symbol is Sr. The name derives from Strontian, a town in Scotland . The mineral strontianite is found in mines in Strontian. The element was discovered by the Scottish chemist and physician Thomas Charles Hope in 1792 observing the brilliant red flame color of strontium. It was first isolated by the English chemist Humphry Davy in 1808. 

Davy also discovered several other elements (potassium, barium, calcium, and strontium) by isolating the metals from their compounds through electrolysis. His work led to the development of electrochemistry, which is the use of electricity as the energy source to break up the oxides of these alkali and alkali earth elements. 

In 1787 William Cruikshank (1745-1795) isolated, but did not identify, strontium from the mineral strontianite he examined. In 1790 Dr. Adair Crawford (1748—1794), an Irish chemist, discovered strontium by accident as he was examining barium chloride. He found a substance other than what he expected and considered it a new mineral. He named the new element strontium and its mineral strontianite after a village in Scotland. In 1808 Sir Humphry Davy treated the ore with hydrochloric acid, which produced strontium chloride. He then mixed mercury oxide with the strontium chloride to form an amalgam alloy of the two metals that collected at the cathode of his electrolysis apparatus. He heated the resulting substance to vaporize the mercury, leaving the strontium metal as a deposit. 

Uranium mineral first is digested with hot nitric acid. AH uranium and radium compounds dissolve in the acid. The solution is filtered to separate insoluble residues. The acid extract is then treated with sulfate ions to separate radium sulfate, which is co-precipitated with the sulfates of barium, strontium, calcium, and lead. The precipitate is boiled in an aqueous solution of sodium chloride or sodium hydroxide to form water-soluble salts. The solution is filtered and the residue containing radium is washed with boiling water. This residue also contains sulfates of other alkahne earth metals. The sohd sulfate mixture of radium and other alkahne earth metals is fused with sodium carbonate to convert these metals into carbonates. Treatment with hydrochloric acid converts radium and other carbonates into chlorides, all of which are water-soluble. Radium is separated from this solution as its chloride salt by fractional crystallization. Much of the barium, chemically similar to radium, is removed at this stage. Final separation is carried out by treating radium chloride with hydrobromic acid and isolating the bromide by fractional crystallization. 

William Cruickshank in 1787 and Adair Crawford in 1790 independently detected strontium in the mineral strontianite, small quantities of which are associated with calcium and barium minerals. They determined that the strontianite was an entirely new mineral and was different from baryta and other barium minerals known at the time. In 1808, Sir Humphry Davy isolated strontium by electrolysis of a mixture of moist strontium hydroxide or chloride with mercuric oxide, using a mercury cathode. The element was named after the town Strontian in Scotland where the mineral strontianite was found. 

For the binary alkaline earth sihcide SiSr, two different structures have been reported. One contains one-dimensionally extended zigzag chains beside isolated Si" atoms [73]. Schafer et al. prepared a modification with the same composition, which instead contained isolated sUicide units of ten atoms. In these units, planar hexagons are substituted in the 1-, 2-, 4-, and 5-ring positions by four additional Si atoms. An isostructural compound was found for germanium as well, but showing defects in this unit in the positions 1, 2, 4, and 5. Both materials could not be obtained from stoichiometric approaches, and their formation obviously is coupled to strontium excess [69] (Fig. 3). 

Sir Humphry Davy, 1778—1829. English chemist and physicist. One of the founders of electrochemistry. Inventor of die safety lamp for miners. He was the first to isolate potassium, sodium, calcium, barium, strontium, and magnesium. Davy in England and Gay-Lussac and Thenard in France, working independently, were die first to isolate boron. 

Sir Humphry Davy isolated the metal in 1808 by the method he had used for calcium and barium (5, 3). In 1924 P. S. Danner of the University of California allowed the oxides of barium and strontium to react with magnesium or aluminum and, upon distilling, obtained both barium and strontium in a high state of purity. His method was a refinement of the one previously used by A. Guntz (33, 34). 

Davy isolates barium, strontium, calcium, and magnesium. Gay-Lussac and Thenard isolate boron. Davy isolates it independently. 

In another example, the high temperature reaction of calcium and strontium sub-nitrides with molybdenum foil has also recently been claimed to produce novel molybdenum ternary nitride oxides which contain isolated [MoN4] tetrahedra in an ordered sub-lattice of and anions. High temperature-high pressure syntheses are also yielding novel metastable structures, such as the spinel analogues mentioned previously. There is therefore an ever-increasing base of nitrides and oxynitrides with diverse structures and potential catalytic interest. 

The periodates 0 the alkaline earths.—C. F. Rammelsberg13 obtained calcium metaperiodate, Ca(I04)2, by the action of periodic acid on a soln. of calcium hydroxide or dimesoperiodate, the solid separates on concentrating the acid soln. similarly, when a soln. of strontium carbonate in an excess of periodic acid is cone, in a desiccator, large, probably triclinic, crystals of hexahydrated strontium metaperiodate, Sr(I04)2.6H2O, are formed. They lose 12-36 per cent, of water when cone, over cone, sulphuric acid, and the remainder at 100°. This salt explodes when heated the aq. soln. has an acid reaction, and gives a precipitate when treated with ammonia. When the attempt is made to concentrate the soln. of barium metaperiodate, Ba(I04)2, prepared in a similar manner, the dimesoperiodate is deposited when the soln. is cone., so that the metaperiodate has not been isolated in a solid state. 

This discovery was soon followed by the isolation of barium, strontium, and calcium. By analogy, it was further inferred that all amorphous powders—alumina, magnesia, etc.—possessing similar properties, were metallic oxides. As a result, when a new earth is now discovered, chemists believe, by faith, that it is the oxide of a metal even in cases where the supposed metal has never been isolated. 

The first oxidative studies on N-acylglycosylamines were conducted on a preparative scale by Niemann and Hays.65 The N-acetyl-D-glucopyranosylamine (69) obtained by acetylation of D-glucopyranos-ylamine with ketene (or by acetylation of this amine, followed by ammonolysis) was oxidized by way of the dialdehyde 70 to the acid 71, isolated as the strontium salt. Hydrolysis of 71 led to D(+)-glyceric acid (72), thus showing the pyranose structure of 69. 

Amide. — It has been pointed out before that europium behaves more or less like the alkaline earths and is closely related to strontium and barium. It is found to react with liquid ammonia at —78° C in much the same way as the alkali metals forming a characteristic deep blue solution. Eu(NH2)2 can be isolated [260] from the blue solution. Recent electron paramagnetic studies [261] of solutions of europium in liquid ammonia showed the presence of complex hyperfine lines arising from Eu2+ (8 7/2, g — 1.990 0.002) besides the characteristic single line of the solvated electron (g = 2.0014 0.0002) K The departure of the Eu2+ <7-value from the free electron value is explained as being due to spin-orbit coupling and a slight admixture (3.5%) of the 6P7/2 state. 

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. 

Strontium. Sr at no 38 at wt 87.62 valence 2 two important radioactive isotopes (out of 12), Sr-89 and Sr-90 four stable isotopes, 88 (82.56% abundance), 86 (9.86% abundance), 87 (7.02% abundance), 84 (0.56% abundance) silvery-white metal, face-centered cubic structure brief exposure to air results in the yel oxide mp 752°, 757°, 769° (separate values) bp 1366°, 1384°, 1390° (separate values) d 2.6g/cc. Sol in acids, ethanol and liq ammonia. CA Registry No [7440-24-6]. Occurs in nature as the sulfate celestine or the carbonate strontianite also found in small quantities associated with Ba, Ca, Pb or K minerals. Prepn is by a) electrolysis of molten Sr chloride in a graphite crucible with cooling of the upper cathodic space to isolate the Sr vapors, or b) thermal redd of the oxide... 

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