Strontium salts

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. 

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 Chromate. Strontium chromate [7789-06-2] SrCrO, is made by precipitation of a water-soluble chromate solution using a strontium salt or of chromic acid using a strontium hydroxide solution. It has a specific gravity of 3.84 and is used as alow toxicity, yellow pigment and as an anticorrosive primer for zinc, magnesium, alurninum, and alloys used in aircraft manufacture (8) (see Corrosion and corrosion control). 

Hardness Calcium, magnesium, barium and strontium salts expressed as CaCOa Chief source of scale in heat exchange equipment, boilers, pipe lines, etc. forms curds with soap interferes wKh dyeing, etc. Softening, distillation, internal boiler water treatment, surface active agents, reverse osmosis, electrodialysis... 

Strontium-gehalt, m. strontium content, -jodid, n. strontium iodide, -oxydhydrat, n. strontium hydroxide, -salpeter, m. strontium nitrate, -salz, n. strontium salt, -was-serstoff, m. strontium hydride. 

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... 

Barium and strontium salts of polystyrene with two active end-groups per chain were prepared by Francois et al.82). Direct electron transfer from tiny metal particles deposited on a filter through which a THF solution of the monomer was percolated yields the required polymers 82). The A.max of the resulting solution depends on the DPn of the formed oligomers, being identical with that of the salt of polymers with one active end-group per chain for DPn > 10, but is red-shifted at lower DPn. Moreover, for low DPn, (<5), the absorption peak splits due to chromophor-chromophor interaction caused by the vicinity of the reactive benzyl type anions. 

Another related host-guest complex has been constructed from citric acid, boric acid, and a strontium salt in a 2 1 1 stoichiometry. In this complex the strontium cation is surrounded by four water molecules, two monodentate carboxyl groups and one oxygen atom of the BO4 unit [161]. 

Characteristic properties of endopectate lyases are the high pH optimum, and a requirement for Ca2+ ions in order to maintain catalytic activity. The pH optimum of various endopectate lyases ranges from 8.0 to 9.5 (Refs. 4, 178, 234, 236, 243). Besides activation by Ca2+ ions, the optimal concentration of which is 1 mM,234,236,244 strontium salts were also considered in the case of Bacillus sp. lyase.234 The enzyme from Pseudomonas sp. was also partly activated by magnesium chloride,178 and for the lyase of Clostridium felsineum, salts of other bivalent cations had an activating effect as well.245 (Ethylenedinitrilo)tetraacetic acid completely inactivated all of the lyases mentioned. The activity of endopectate lyase from Pseudomonas was also lessened in the presence of sodium chloride, potassium chloride, and dipotassium hydrogen phosphate (K2HP04). 

Pelletizing, in pyrometallurgy, 16 140 Pelouze reaction, 17 227 Peltier effect, 21 555 24 428 Pelton wheel turbine, 26 85 Pemanent Red 2B, Strontium Salt, pigment for plastics, 7 366t PEM fuel cell (PEMFC), 12 202-203 PEN, 10 222. See also Poly(ethylene 2,6-naphthalenedicarboxylate) (PEN) Penaeid shrimp, aquacultural chemical needs, 3 209... 

The strontium lake performs like barium lakes of P.R.53 1 and is equally fast to organic solvents, to alkali and acid. Both types are equally heat stable and light-fast, for instance in print. Coloristically, the strontium salt of P.R.53 is yellower, but it does not quite match the shade of the above-mentioned novel crystal modification of the barium lake. P.R.53 3 is generally being used for the same purposes as P.R.53 . 

Initially, these lakes were precipitated onto inorganic carrier materials. It is interesting to note that this group of colorants was originally used for pigments in paints. Application in the textiles market followed later. Today, it is mainly the calcium and barium salts, but also manganese and, less frequently, strontium salts that have the largest sales volume. 

Both calcium and manganese salts are commercially available. The US market also offers strontium salts and mixed barium/calcium lakes. Although they are important pigments in the USA, P.R.52 types generally have little commercial importance in Europe. These types are referred to in the USA as IBB toners. 

The following salts have been produced the sodium salt (P.R.58), the barium salt (P.R.58 1), the calcium salt (P.R.58 2), the strontium salt (P.R.58 3), and the manganese lake (P.R.58 4). The commercial success of each type varies considerably by the region but has generally decreased considerably as the pigments were replaced by other lakes. P.R.58 4 is unique in that it is the only representative which has remained in the European market. 

The frequencies of the v A ) vibrations have been obtained from the Raman spectra of Sr3(V04)2 and Ba3(V04)2- Values of 861 and 855 cm"i were measured for the strontium salt and 839 cm i for the barium salt. These modes were too weak to be observed in the IR spectrum (52). 

The chemistry that governs barium salts, as used in green stars, is somewhat analogous to that of the strontium salts employed in red stars since both elements are found in the same group of the periodic table. While the use of compounds such as strontium chloride, strontium chlorate or strontium perchlorate might be considered to be appropriate... 

Other coloured flames follow similar physico-chemical phenomena but operate in different regions of the spectrum. Consequently, the maker of the coloured lance has at his disposal copper salts for blue, strontium salts for red, sodium salts for yellow and barium salts for green, as shown in Table 10.2. 

Apionic Acid, Its Phenylhydrazide and Its Calcium and Strontium Salts. The oxidation of a crude apiose solution with bromine water... 

Strontium and its compounds are mostly derived from celestite, SrS04. The mineral is converted to its carbonate by heating with sodium carbonate. Alternatively, the mineral may be reduced to sulfide by heating with coke. The carbonate or the sulfide is then converted to other strontium salts. 

Strontium carbonate occurs in nature as mineral strontianite. The compound is used in pyrotechnics and ceramic ferrites. It also is used in making iridescent glass for color television tubes. Other uses are in refining sugar and preparing other strontium salts. 

Strontium chloride is used to produce strontium metal by electrolysis. It also is used to prepare other strontium salts, as a desensitizer in dentistry, and in pyrotechnics. 

Dr. Crawford showed in this paper that the salt (strontium chloride) obtained by dissolving the new mineral in hydrochloric acid differs in several respects from barium chloride. It is much more soluble in hot water than in cold, the strontium salt is much the more soluble in water and produces a greater cooling effect, and these two chlorides have different crystalline forms. He concluded therefore that the mineral which is sold at Strontean [sic] for aerated terra ponderosa possesses different qualities from that earth, although at the same time it must be admitted that in many particulars they have a very near resemblance to each other. He also stated that it is probable that the Scotch mineral is a new species of earth which has not hitherto been sufficiently examined and that Mr. Babington. . . has for some time entertained a suspicion that the Scotch mineral is not the true aerated terra ponderosa. In 1790 Dr. Crawford sent a specimen of the new mineral (strontianite, strontium carbonate) to Richard Kirwan for analysis (50, 66). 

Strontium salts were very rare at that time, and Talbot was indebted to Michael Faraday for the specimen he used. 

Calcium and strontium salts of hyaluronic acid, at relative humidities of 66-92%, crystallize in a trigonal unit-cell, with a = b — 2.093 nm and c = 2.83 nm. On drying, the base-plane dimensions reduce to a = b = 1.832 nm, with c = 2.847 nm. Seven water molecules per disaccharide residue exist in the wet form, and two in the dry form. The adjacent chains are antiparallel, and the space group is P3212. The three disaccharide units in the 3(- 0.94) helix are nonequi-... 

A similar problem concerning the strontium salt will be discussed here by Professor Van Beylen, while the problem of the barium salt of the poly-styrene endowed with two growth propagating ends will be dealt with by Dr. Francois. 

Anionic Polymerization of the Strontium Salt of One-Ended Living Polystyrene in Tetrahydrofuran and Tetrahydropyran... 

In the present communication the strontium salt of one-ended living polystyrene (SrS2) was studied In tetrahydrofuran (THF) and tetrahydropyran (THP), In order to check the validity of the triple Ion mechanism. The Ionic dissociation of SrS2 In THP was expected to be smaller than In THF and therefore It was thought that perhaps a contribution to the propagation from species, other than the free S anions, would be detectable. 

Preparation of the strontium salt of one-ended living polystyrene (SrS )... 

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