Magnesium number

Draw in a diagram Na20/CaO vs FeO/MgO, the curve representing the hybrids (mix = hyb) between a basalt (a = bas) and a gneiss (fi=gn), whose compositions are listed in Table 1.7a. Discuss the relationship between CaO and the magnesium number mg which is the atomic ratio Mg/(Fe + Mg)... 

Lunar prospector measurements of Al203 and magnesium number, Mg/(Mg+Fe) (black circles). These compositions are consistent with those of major lunar rock types from the Apollo collection (boxes). Modified from Prettyman et al. (2006). 

Fig. 14.18 The flows and dikes on Plogen and Basen have tita-nium/yttrium (Ti/Y) ratios less than six which is characteristic of low-titanium basalts. The magnesium number of these rocks, deflned as the atomic (Mg/Mg-i-Fe +) ratio, varies widely from about 0.4 to 0.7 (Adapted from Luttinen and Siivola (1997))...

It increased by one unit from one element to the next, for example magnesium 12. aluminium 13. This is clearly seen in Figure 13. Z was called the atomic number it was found to correspond to the charge on the nucleus of the atom (made up essentially of protons and neutrons), a charge equal and opposite to the number of extra nuclear... 

The rate of the reaction decreases with increasing number of substituents in the acetylenic halide, and it is higher with acetylenic bromides than with the corresponding chlorides. Methyl magnesium iodide gives equal amounts of 1,1- and 1,3--substitution products, whereas tert.-butylmagnesium bromide does not react. However, for some tert.-butyl substituted allenes there exists an attractive com-... 

Alternative methods for its generation have made it possible to use benzyne as an intermediate m a number of synthetic applications One such method involves treating o bromofluorobenzene with magnesium usually m tetrahydrofuran as the solvent... 

Miscellaneous. Flame-resistant cross-linked polyethylene can be made with a number of fluoroborates and antimony oxide. This self-extinguishing material may contain the fluoroborates of NH, Na", K", Ca ", Mg ", Sr ", or Ba " in amounts of 4—20% (76). Magnesium fluoroborate cataly2es the epoxy treatment of cotton fabrics for permanent-press finishes (77) (see Textiles). 

Magnesium [7439-95-4] atomic number 12, is in Group 2 (IIA) of the Periodic Table between beryllium and calcium. It has an electronic configuration of 1T2T2 3T and a valence of two. The element occurs as three isotopes with mass numbers 24, 25, and 26 existing in the relative frequencies of 77, 11.5, and 11.1%, respectively. 

Machining. Magnesium is the easiest of all stmctural metals to machine (120). Because of this machinabiUty, it is sometimes used in apphcations where a large number of machining operations are required. The machinability of magnesium alloys relative to that of other metals based on the lowest power required to remove 16 cm of metal and when magnesium is assigned a value of unity, is (120) ... 

A number of synthetic polymers having the abHity to control filtration rates at high temperature and in the presence of calcium and magnesium have also been developed (88). Such materials include vinyl sulfonate—vinyl amide copolymers (89,90), a copolymer of AMPS and A/,A/-dialkyl (meth) acrylamide (91) and a sulfonated hydroxylated polymer (92). AppHcation levels for these materials range from 5 to 18 kg/m (2—6 lb /bbl). Sulfonated asphalt is also used for high temperature filtration control. 

The mixture is kept for 3 hours at 105°C after the oxide addition is complete. By this time, the pressure should become constant. The mixture is then cooled to 50°C and discharged into a nitrogen-filled botde. The catalyst is removed by absorbent (magnesium siUcate) treatment followed by filtration or solvent extraction with hexane. In the laboratory, solvent extraction is convenient and effective, since polyethers with a molecular weight above about 700 are insoluble in water. Equal volumes of polyether, water, and hexane are combined and shaken in a separatory funnel. The top layer (polyether and hexane) is stripped free of hexane and residual water. The hydroxyl number, water, unsaturation value, and residual catalyst are determined by standard titration methods. 

Reaction of (T)-(-)-2-acetoxysuccinyl chloride (78), prepared from (5)-mahc acid, using the magnesiobromide salt of monomethyl malonate afforded the dioxosuberate (79) which was cyclized with magnesium carbonate to a 4 1 mixture of cyclopentenone (80) and the 5-acetoxy isomer. Catalytic hydrogenation of (80) gave (81) having the thermodynamically favored aH-trans stereochemistry. Ketone reduction and hydrolysis produced the bicycHc lactone acid (82) which was converted to the Corey aldehyde equivalent (83). A number of other approaches have been described (108). 

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