INDEX salts

To eliminate the problems associated with the washing step, Okazaki, Smith, and Moodie proposed a CEC procedure in which salts are not removed between the index cation saturation and extraction steps. Rather, the anion of the salt providing the index cation is analyzed in the final extract. In accordance with electrical neutrality, the CEC is then equal to the total quantity of index cations removed during extraction minus the quantity of index anions removed simultaneously. The main potential source of error from this procedure arises from anion repulsion, if the quantity of index salt remaining after saturation is merely calculated from the weight of solution retained and its initial (or average) concentration. This error minimized if the index solution is lowered to approximately 0.1 M during the final two saturation washes. The error is eliminated if the quantities of index salt are analytically determined instead. 

The concentration of the index salt solution should not be high. Early measurements using 1 M salt solutions, to insure complete replacement and flocculation, yielded low CEC measurements because anion repulsion is significant at these concentrations and neutralized a significant portion of the colloid s charge. The CEC measurement is one of many examples in soil chemistry of the complexity of a seemingly simple experiment. 

Thioethers usually yield sulphonium salts when warmed with ethyl iodide and allowed to cool. The physical properties (b.p., density and refractive index) are useful for identification purposes. 

Lead oxide is used in producing fine "crystal glass" and "flint glass" of a high index of refraction for achromatic lenses. The nitrate and the acetate are soluble salts. Lead salts such as lead arsenate have been used as insecticides, but their use in recent years has been practically eliminated in favor of less harmful organic compounds. 

Salt extraction Salt flotation Salt index... 

Potassium nitrate is being used increasingly on intensive crops such as tomatoes, potatoes, tobacco, leafy vegetables, citms, and peaches. The properties that make it particularly desirable for these crops are low salt index, nitrate nitrogen, favorable N K20 ratio, negligible CU content, and alkaline residual reaction in the soil. The low hygroscopicity of KNO (Table 9) leads to its use in direct appHcation and in mixtures. It is an excellent fertilizer but the high cost of production limits its use to specialty fertilizers. 

Lithium Niobate. Lithium niobate [12031 -64-9], LiNbO, is normally formed by reaction of lithium hydroxide and niobium oxide. The salt has important uses in switches for optical fiber communication systems and is the material of choice in many electrooptic appHcations including waveguide modulators and sound acoustic wave devices. Crystals of lithium niobate ate usually grown by the Czochralski method foUowed by infiltration of wafers by metal vapor to adjust the index of refraction. 

Refractive Index. The effect of mol wt (1400-4000) on the refractive index (RI) increment of PPG in ben2ene has been measured (167). The RI increments of polyglycols containing aUphatic ether moieties are negative drj/dc (mL/g) = —0.055. A plot of RI vs 1/Af is linear and approaches the value for PO itself (109). The RI, density, and viscosity of PPG—salt complexes, which maybe useful as polymer electrolytes in batteries and fuel cells have been measured (168). The variation of RI with temperature and salt concentration was measured for complexes formed with PPG and some sodium and lithium salts. Generally, the RI decreases with temperature, with the rate of change increasing as the concentration increases. 

Historically, the use of xanthines has been hampered by poor aqueous solubiUty, rapid but highly variable metaboHsm, and the existance of a low therapeutic index. SolubiUty problems were partially solved by the preparation of various salt forms, eg, aminophylline. However, it was since recognized that the added base in aminophylline only increases solubiUty by increasing pH and thus does not affect the rate of absorption from the gut (65). Thus, in more recent medical practice, theophylline is commonly dispensed in anhydrous form and aminophylline is only recommended for iv adrninistration. 

Chlorine. Nearly all chlorine compounds are readily soluble in water. As a result, the major reservoir for this element in Figure 1 is the ocean (5). Chloride, as noted earHer, is naturally present at low levels in rain and snow, especially over and near the oceans. Widespread increases in chloride concentration in mnoff in much of the United States can be attributed to the extensive use of sodium chloride and calcium chloride for deicing of streets and highways. Ref. 19 points out the importance of the increased use of deicing salt as a cause of increased chloride concentrations in streams of the northeastern United States and the role of this factor in the chloride trends in Lake Ontario. Increases in chloride concentration also can occur as a result of disposal of sewage, oil field brines, and various kinds of industrial waste. Thus, chloride concentration trends also can be considered as an index of the alternation of streamwater chemistry by human development in the industrialized sections of the world. Although chlorine is an essential element for animal nutrition, it is of less importance for other life forms. 

Eor the many details of constmcting or interpreting stmctures and systematic names, the Hterature on nomenclature and indexing (6) can be consulted. Systematic nomenclature is illustrated by the Chemicaly hstracts name of the sodium iron(III) EHPG chelate sodium [[N,N -l,2-ethanediylbis[2-(2-hydroxyphenyl)glyciQatol]](4-)-N,N, 0,0, 0, 0 ]ferrate(l-) [16455-61-1], The ferrate anion (12) [20250-28-6] and the potassium salt [22569-56-8] are also Hsted ia Chemical Abstracts (7). 

Al2(S04)j in aqueous solution is most commonly known as aluminum sulfate solution. The CAS (Chemical Abstract Service) Index is Sulfuric Acid, Aluminum Salt (3 2) . Its CAS number is 10043-01-3. Aluminum sulfate, solution, technical grade is a clear, white to slightly yellow brown liquid. 

The tartrate salt is recrystallized by dissolving in hot methanol, filtering, adding hot ethanol to the filtrate and cooling. The product is collected and air-dried. MP 148°-150°C. A second crop is obtained from the filtrate for a total yield of 59%. The tartrate is then metathe-sized with pamoic acid (Merck Index 6867) to give pyrantel pamoate as the product. 

LSI (Langelier Saturation Index) an indication of the corrosive (negative) or scale-forming (positive) tendencies of the water. Hardness the total dissolved calcium and magnesium salts in water. Compounds of these two elements are responsible for most scale deposits. Units are mg/l as CaCOs. 

Typically, RO plants require a RW supply with a salt density index (SDI) of below 3.0 (ideally below 1.0) to prevent excessive membrane fouling. 

Compounds containing the neutral (formally zwitterionic) group =N2 attached by one atom to carbon are named by adding the prefix diazo- to the name of the parent compound (Rule 931.4), e.g., diazomethane, ethyl diazoacetate. Diazo is a so-called characteristic group appearing only as a prefix in substitutive nomenclature. Chemical Abstracts and Beilstein indexing of diazo compounds is analogous to that mentioned above for diazonium ions and salts, but Diazo compounds is not... 

For the determination of the molecular weight (Mw) by light scattering, the number of solvent systems is limited. The refractive index difference should be at least 0.1 and the solvent should not have an electrolytic effect. Useful solvents include formic acid containing KC1 salt and fluorinated alcohols. 

The hydrophobicity index is also suitable for correlating the cM values of various substituted sodium alkane 1-sulfonates [68]. The perfluoroalkyl substituent, e.g., 8 17 has a pronounced hydrophobic effect (/ = 1.66 at 75°C, sodium salt), whereas the hydrophilic disulfonates have values distinctly below 1 (for a-disulfonates, / = 0.75 was derived [70]). Further, it was somewhat surprisingly shown that substituents like 1-hydroxymethyl, 3-hydroxyethoxy, or even the hydroxyethoxyethoxy groups have hydrophobic effects. 

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