Strontium derivatives

Belcher et al. reported the synthesis of the strontium derivatives of tpm, ppm, and hpm by addition of the /3-diketone to an aqueous solution of the metal chloride (see later discussion for other method using MC12 salts). After adjustment of the solution pH to 7 with ammonia, the metal bis(/3-diketonate) compounds precipitate as white solids.151 The same authors have also reported the synthesis of the calcium derivatives of these three ligands by addition of the ligand to calcium hydroxide suspended in methanol. The compounds are precipitated by addition of water. The barium derivatives, however, were prepared directly by addition of the /3-diketone to an aqueous solution of barium hydroxide. The MU(L)2 2HzO (M = Ca, Sr, or Ba L = tpm, ppm, or hpm) compounds are all similar in composition. Metal hydroxide methods have also been used for the preparation of M(fod)2,152 M(hfac)2(H20) ,153 (enH2)] 5[Ba(hfac)5] ... 

In the dissolved load, the preferential dissolution of the different types of lithology or mineral can cause large variations in trace-element abundances in rivers. A classical tracer of rock dissolution is strontium. The isotopic ratio of strontium in river waters is, to a first approximation, explained by mixing between different sources. Rain, evaporite dissolution, and carbonate and silicate weathering are the predominant sources of strontium in rivers (see Chapter 5.12). Examples of the use of Ca/Sr, Na/Sr, and Sr isotopic ratios to quantify the proportion of strontium derived from carbonate weathering in large basins can be found in Negrel et al. (1993)... 

Figure 21 Structure of the strontium derivative Li4Sr2(H2L)(02CC4H9)2(DMF)8 formed from Pr calix[8]...

Alkaline-earth alkoxides are insoluble and involatile in contrast to the double alkoxides formed by dissolving the alkaline earth metal in a solution of niobium or tantalum isopropoxide in propan-2-ol. With the exception of the magnesium derivative which decomposes on heating, they can be sublimed in vacuo, thermal stability diminishing in the order Ba > Sr > Ca. The calcium and strontium derivatives are monomeric in refluxing benzene, the others are insoluble. Attempts to elucidate structures by n.m.r. spectroscopy were foiled by the rapid exchange of geminal dimethyl protons (see also p. 66). 

Radioactive Strontium. Nervous system disorders (weakness, apathy, fatigue) were reported in the Techa River population that was chronically exposed to combined external gamma radiation and internal radiation from 90Sr and 137Cs (Akleyev et al. 1995). Neurological effects were observed at chronic dose rates in excess of 40-50 rad (0.4-0.5 Gy) per year and persisted for 14-20 years in the exposed population. However, it is not clear to what extent strontium-derived radiation contributed to neurological effects,... 

The whole-rock Rb-Sr date of 1789 141 Ma (Paleoproterozoic) is the time when these rocks were recrystallized during regional metamorphism to amphibolite grade and the strontium they contained was isotopically homogenized so that all three specimens had the same initial Sr/ Sr ratio of 0.7059 0.0041. This value indicates that their protoliths contained strontium derived from the lithospheric mantle in the form of volcanic rocks or their weathering products. 

The low initial Sr/ Sr ratio of the Hope Granite in the Gabbro Hills indicates that the granitic magma contained strontium derived from mafic volcanic rocks in the underlying lithospheric mantle. 

We prefer the second alternative because the Sr/ Sr ratios of most Cenozoic lavas analyzed by Stuckless and Ericksen (1976) and by Jones and Walker (1972) provide no evidence that the magma was contaminated by strontium derived from the granitic basement rocks. The only exception is the sample of trachyte (CC-82, Fig. 16.7) which has a high Sr/ Sr ratio of 0.70501 (Stuckless and Ericksen 1976). 

Strontium derived from seawater is even more abundant in soil salts along the coast of Ross Island analyzed by Jones et al. (1983) and Fame and Jones (1989). The Sr/ Sr ratios of these salts in Fig. 16.23 and Appendix 16.8.2 range widely from 0.70344 2 (calcite, Castle Rock, Hut Point Peninsula, elevation 413 m) to 0.70912 3 (thenardite. Trachyte Hill, Cape Bird, elevation 2 m). The calcite on Castle Rock contains strontium of volcanic origin, whereas the strontium in thenardite along the beach at Cape Bird is of marine origin. 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

Solvay America Inc., 144, 248 Solvay Barium and Derivatives S.p.A., 144, 180 Solvay Barium Strontium GmbH, 144 Solvay Fluor and Derivatives GmbH, 145 Solvay Group SA, 144... 

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... 

The low-temperature (/1-)AE3(BN2)2 phases exhibit two distinct structures for AE = Ca and Sr that can be derived from the cation disordering in their respective high-temperature phases. For / -Ca3(BN2)2 an orthorhombic (Cmca) superstructure of the cubic cell with fi-a bo a, Cq ly l a was obtained, in which the former 8f sites are occupied by seven calcium ions in an ordered fashion. In contrast, the structure of / -Sr3(BN2)2 is simply the result of a transition from a cubic body-centered (Im3m) into a primitive structure (Pm3m), in which the former 2 a position (0, 0, 0 1/2, 1/2, 1/2) is split into two independent positions, of which only one is occupied by strontium (Fig. 8.6). 

Strontium isotopes. Strontium isotopic compositions ( Sr/ Sr) of anhydrite, gypsum and barite from Kuroko deposits are summarized in Fig. 1.45 (Farrell et al., 1978 Honma and Shuto, 1979 Farrell and Holland, 1983 Yoneda et al., 1993 Yoneda and Shirahata, 1995). Sr/ Sr values of anhydrite and gypsum are slightly lower than that of seawater, suggesting that most of the strontium was derived from seawater, but a small amount of... 

Hemond C, Condomines M, Fourcade S, Allegre CJ, OskarssonN, Javoy M (1988) Thorinm, strontium and oxygen isotopic geochemistry in recent tholeiites from Iceland crastal influence on mantle-derived magmas. Earth Planet Sci Lett 87 273-285... 

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... 

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