Magnesium cation effects

Valyashko and Gode (414) have summarized the conditions necessary for formation of borates of sodium, potassium, ammonium, calcium, and magnesium. The effect of varying the cation is to alter the type of borate that is stable in contact with the aqueous solution. The stability ranges for solid phases in the sodium and calcium systems are shown in Table V. 

Oelschlaeger P, Klahn M, Beard WA et al (2007) Magnesium-cationic dummy atom molecules enhance representation of DNA polymerase beta in molecular dynamics simulations improved accuracy in studies of structural features and mutational effects. J Mol Biol 366 687-701. doi 10.1016/J.Jmb. 2006.10.095... 

The effect of micelle formation on the hypochlorite-induced decomposition of toxic esters of phosphorus has been examined (Dubey et al., 2002). The presence of the calcium and magnesium cations in sea water appears to accelerate the hydrolysis (Demek et al., 1970). 

Metal cations were eluted with eluent containing magnesium perchlorate. The divalent magnesium cation is a more effective eluent than H+ or Na", so lower concentrations are needed. In the range 0.5 mM to 10 mM Mg ", the linear plots of log k vs. log [Mg " ] for several divalent metal cations gave a slope close to the theoretical value of-1.0 (Table 5.7). 

Soap Soap has been known since antiquity as a surfactant for removal of soil from textiles. Soap is readily made by basic hydrolysis (saponification) of animal fats (fatty esters of glycerol). Soap is the resultant sodium sal t of the fatty acids, with the composition depending on the source of fatty acid esters. Soap suffers from one major deficiency as a surfactant in hard water containing calcium and magnesium cations, the sodium ion in soap is replaced by these multivalent ions to form insoluble salts which caimot act effectively as surfactants. 

We will discuss the concrete case of a-alumina (AI2O3), which can, at first approximation, be considered as the Schottky solid, that is, it contains aluminum vacancies and oxygen vacancies. Let us consider the effect of introduction of magnesium cations in substitution (valence 2) at the concentration C. We assume that the solid is closed compared with magnesium and thus C is a constant. 

Addition of a salt can transform the shale by cation exchange to a less sensitive form of clay, or reduce the osmotic swelling effect by reducing the water activity in the mud below that which occurs in the shale. These effects depend on the salt concentration and the nature of the cation. Salts containing sodium, potassium, calcium, magnesium, and ammonium ions ate used to varying degrees. 

The most commonly observed effect of current flow is the development of alkaline conditions at the cathode. On bare metal this alkaline zone may exist only at the metal surface and may often reach pH values of 10 to 12. When the soil solution contains appreciable calcium or magnesium these cations usually form a layer of carbonate or hydroxide at the cathodic area. On coated lines the cations usually move to holidays or breaks in the coating. On failing asphalt or asphalt mastic type coatings, masses of precipitated calcium and magnesium often form nodules or tubercles several centimetres in diameter. 

The effect of the nature of the cation, such as sodium, ammonium, magnesium, and alkanolamines, was studied by Fischer [424] and seems to be negligible. 

Magnesium and calcium are by far the most important members of the group. Magnesium is, in effect, the doorway to life it is present in every chlorophyll molecule and hence enables photosynthesis to take place. Calcium is the element of rigidity and construction it is the cation in the bones of our skeletons, the shells of shellfish, and the concrete, mortar, and limestone of buildings. 

The running of parallel reactions of hydrolysis, ammonolysis and depolymerization of apple pectin in aqueous solution of ammonia (IM) at 25 C were investigated. It was examined the effects of monovalent cations (Na, K", NH4 ) and divalent cations (Ca, Mg ) when they were added as chloride salts. It was found that the relative rates of the above mentioned reactions, depend on the nature and concentration of the added salts as well. The chlorides of sodium, potassium and calcium accelerate hydrolysis and depolymerization, while magnesium chloride delays these reactions. Ammonolysis was increased in cases of ammonium chloride addition. 

As we have already shown, the presence of cations in orthophosphoric acid solution can have a decisive effect on cement formation. As noted above, Kingery (1950b) found it necessary to modify orthophosphoric add, by the addition of calcium, to obtain cement formation with calcium oxide. Also, Finch and Sharp (1989) had to modify orthophosphoric add, with either ammonium or aluminium, to achieve cement formation with magnesium oxide. 

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