Magnesium/calcium ratio

The interplay of factors leading to the formation of carbonate rocks is extremely complicated, but several avenues of investigation have yielded fruitful results. These approaches include studies of surface energies, isotopic composition and radiochemistry (including the use of carbon-14 to study the rates of carbonate deposition), solubilities under ambient conditions, and the effect of magnesium-calcium ratios in the solutions from which carbonate minerals are precipitated. 

Yadav, J. S. P. and I. K. Girdhar. 1980. The effects of different magnesium calcium ratios and sodium adsorption ratio values of leaching water on the properties of calcareous versus noncalcareous soils. Soil Sci. 131 194-198. 

Nature, however, has provided us with a long-term solubility experiment. The well waters of Florida show a constant ratio of magnesium to calcium ([Mg ]/[Ca ] = 0.8 0.1). The tendency for subsurface waters to have such a nearly constant magnesium-calcium ratio suggests that waters in porous dolomitic limestones might have equilibrated with both the calcite and dolomite phases [For a general treatment on dolomites in groundwaters, see, for example, Plummer et al. (1990).]... 

Goldschmidt predicted from his empirical rule that calcium chloride would not have the fluorite structure, and he states that on investigation he has actually found it not to crystallize in the cubic system. Our theoretical deduction of the transition radius ratio allows us to predict that of the halides of magnesium, calcium, strontium and barium only calcium fluoride, strontium fluoride and chloride, and barium fluoride, chloride,... 

The opposite trend in concentrations of the earth-alkaline ions induced a remarkable and statistically significant change in the magnesium to calcium ratio (Fig. 12). It is worth mentioning that the seasonal minimum in the ratio occurs in summer when Mg and Ca also show their minima. The relatively larger seasonal decrease in... 

Water from the sea obviously contains high levels of sodium and chlorine. Sea water, though, differs from other forms of salt water and fresh water in the ratio of magnesium calcium. In fresh water, the ratio of magnesiumxalcium is from about 1 2 to 1 3. In sea water, the ratio can range from 3 1 to as high as 4 1. This difference helps to distinguish sea water from fresh water. TABLE 4-13 provides information on the concentration of various components found in sea water. 

Rushdi, A.I., Pytkowicz, R.M., Suess, E. Chen, C.T. (1992) The effects of magnesium-to-calcium ratios in artificial seawater, at different ionic products, upon the induction time, and the mineralogy of calcium carbonate a laboratory study. GeoL Rundschau, 81, 571-578. 

Fig. 7-23. Scatter diagrams for iron, titanium, magnesium, calcium, vanadium, and chromium in the atmospheric aerosol versus aluminum as reference element. Concentrations are given in units of ng/ m3. Symbols indicate the type of sampling site O marine, A marine-influenced, 9 remote continental, Antarctic. The range of X/Al ratios in crustal rock is shown by the solid lines and X/Al ratios in soil by the dashed lines. [Adapted from Rahn (1975b).]...

Description Produced by micronization of natural mixed mineral (huntite, hydromagnesite) hydrate is efficient FR for processing temperatures up to 260°C. also acid scavenger in chlorine-containing compounds magnesium calcium carbonate is for processing temperatures up to about 400°C, with improvement to mechanical properties from platelet structure and high aspect ratio ... 

Only 11 elements can be considered major components of seasalt the cations sodium, potassium, magnesium, calcium and strontium, and the anions chloride, sulphate, bromide, hydrogen carbonate (carbonate), borate (borid acid) and fluoride. These major dissolved constituents (concentrations > 1 mg/kg in ocean waters) make up > 99 % of the soluble ionic species of seawater. The elemental ratios are relatively constant throughout the world ocean, and their concentrations change due to the addition or substruction of water only (concept of conservatism ). Therefore, it is possible to characterize the composition by determining only one constituent that is easy to measure and is conservative in its behaviour. An example is chlorinity (Cl, as defined in Section 11.2.4). 

Becker, J.S., Fiillner, K., Seeling, U.D., Fornalczyk, G., and Kuhn, A.J. (2008) Measuring magnesium, calcium and potassium isotope ratios using ICP-QMS with an octopole collision cell in tracer studies of nutrient uptake and translocation in plants. Anal. Bioanal. Chem., 390, 571-578. 

The Elements Beryllium (Be), Magnesium (Mg), and Calcium (Ca) all formed oxides in fhe ratio of one afom per oxygen atom RO Boron (B) and Aluminum (Al) formed R2O3 Carbon (C) and Silicon (Si) formed RO2... 

The amount of calcium in a sample of urine was determined by a method for which magnesium is an interferent. The selectivity coefficient, Rca.Mg> for the method is 0.843. When a sample with a Mg/Ca ratio of 0.50 was carried through the procedure, an error of-3.7% was obtained. The error was +5.5% when a sample with a Mg/Ca ratio of 2.0 was used. 

Tricalcium phosphate, Ca2(P0 2> is formed under high temperatures and is unstable toward reaction with moisture below 100°C. The high temperature mineral whidockite [64418-26-4] although often described as P-tricalcium phosphate, is not pure. Whidockite contains small amounts of iron and magnesium. Commercial tricalcium phosphate prepared by the reaction of phosphoric acid and a hydrated lime slurry consists of amorphous or poody crystalline basic calcium phosphates close to the hydroxyapatite composition and has a Ca/P ratio of approximately 3 2. Because this mole ratio can vary widely (1.3—2.0), free lime, calcium hydroxide, and dicalcium phosphate may be present in variable proportion. The highly insoluble basic calcium phosphates precipitate as fine particles, mosdy less than a few micrometers in diameter. The surface area of precipitated hydroxyapatite is approximately... 

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