Magnesium origin

If we assume that calcium and magnesium originate exclusively from carbonate, in areas with no acidification the sum of calcium and magnesium should equal alkalinity (Aik [HCOs"]). 

Globally, then, oxygen, neon and magnesium originate in hydrostatic shell combustion and the quantity synthesised and ejected increases with the mass of the progenitor star, whilst sulphur, argon, calcium and iron are essentially due to explosive nucleosynthesis and the ejected mass is much less variable from one star to another. 

The special role of 2p photoionization in magnesium originates in the simplicity of the system which, however, is still complicated enough to exhibit typical electron-electron interactions. The main advantages are the following ... 

It was originally separated from zirconium by repeated recrystallization of the double ammonium or potassium fluorides by von Hevesey and Jantzen. Metallic hafnium was first prepared by van Arkel and deBoer by passing the vapor of the tetraiodide over a heated tungsten filament. Almost all hafnium metal now produced is made by reducing the tetrachloride with magnesium or with sodium (Kroll Process). 

Magnesium Corporation of America (Alagcorp) Process. The magnesium facihty ia Rowley, Utah, originally built by NL Industries ia 1972, was purchased by AMAX, Inc., ia 1980, sold ia 1989 to a private investment group, and was named Magcorp. 

AH metals come originally from natural deposits present in the earth s cmst. These ore deposits result from a geological concentration process, and consist mainly of metallic oxides and sulfides from which metals can be extracted. Seawater and brines are another natural source of metals, eg, magnesium (see Chemicals frombrine Magnesium and magnesium alloys Ocean raw materials). Metal extracted from a natural source is called primary metal. 

Selective solution of the aluminum from the ahoy using a volatile metal, such as mercury, lead, bismuth, cadmium, magnesium, or zinc, has been investigated. After extracting the aluminum from the original ahoy into the volatile metal, the volatile metal is distilled, leaving pure aluminum. Neither electrolysis nor volatile metal extraction can extract aluminum from iron aluniinide [12004-62-3J, EeAl, titanium aluniinide [12004-78-3] TiAl, or Al C. ... 

The other impurities originate from tetrachloride, residual gases in the reactor, helium or argon impurities, and magnesium or sodium residues. 

The egg shell is 94% calcium carbonate [471-34-17, CaCO, 1% calcium phosphate [7758-23-8] and a small amount of magnesium carbonate [546-93-0]. A water-insoluble keratin-type protein is found within the shell and in the outer cuticle coating. The pores of the shell allow carbon dioxide and water to escape during storage. The shell is separated from the egg contents by two protein membranes. The air cell formed by separation of these membranes increases in size because of water loss. The air cell originally forms because of the contraction of the Hquid within the egg shell when the temperature changes from the body temperature of the hen at 41.6°C to a storage temperature of the egg at 7.2°C. 

Ash is the inorganic residue that remains after the coal has been burned under specified conditions, and it is composed largely of compounds of sihcon, aluminum, iron, and calcium, and minor amounts of compounds of magnesium, sodium, potassium, phosphorous, sulfur, and titanium. Ash may vaiy considerably from the original mineral matter, which is largely kaolinite, iUite, montmoriUonite, quartz, pyrites, and gypsum. 

The original cyclooligomerization noted above was conducted using alkyl aluminum, zinc and magnesium compounds ". Both open-chained and cyclic polymers were obtained in addition to dioxane. The principal macrocyclic component of the mixture was apparently 12-crown-4 (EO-4) which was said to be valuable as a high boiling neutral solvent... . " The reaction is shown below in Eq. (1.2). 

The most widely used procedures for the preparation of the indole magnesium halides are based on the method originally described by Oddo in 1911, and consist of adding a solution of indole or an indole derivative, in dry diethyl ether, to a solution of an alkyl magnesium... 

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