Compound ionic nature

Chem. Descrip. phosphated ester compound Ionic Nature Anionic... 

Chem. Descrip. Quat. compound Ionic Nature Cationic Uses Softener, antistat in textiles Properties Paste Emkalon BaseC-100 [Emkay ]... 

An electron impact mass spectrum of calcium leuco-vorin has not been obtained because the compound is not sufficiently volatile. It would be difficult to isolate the free acid without first dehydrating the compound. Due to its ionic nature, calcium leucovorin will not dissolve in common silylating reagents. Field desorption, another mass spectral technique, generally lends itself more to compounds like leucovorin. Indeed, this technique has been applied successfully to methotrexate and other folic acid analogs.1 ... 

Water. It should come as no surprise that ordinary water can be an excellent solvent for many samples. Due to its extremely polar nature, water will dissolve most substances of likewise polar or ionic nature. Obviously, then, when samples are composed solely of ionic salts or polar substances, water would be an excellent choice. An example might be the analysis of a commercial iodized table salt for sodium iodide content. A list of solubility rules for ionic compounds in water can be found in Table 2.1. 

Degree, of Ionic Nature in Solid Rare Earth Compounds... 

Nowadays we look with other eyes at organometallic compounds the family of which has expanded enormously. Some members of this family are soluble in water due to their ionic nature the legions of anionic carbonylmetallates (e.g. [Ni(CN)(CO)3] ) and cationic bisphosphine Rh-chelate complexes (e.g. [Rh(BDPP)(COD)] ) just come to mind. Others obtain their solubility in water from the well soluble ligands they contain these can be ionic (sulfonate, carboxylate, phosphonate, ammonium, phosphonium etc. derivatives) or neutral, such as the ligands with polyoxyethylene chains or with a modified urotropin structure. 

The extensive use of alkyllithium initiators is due to their solubility in hydrocarbon solvents. Alkyls or aryls of the heavier alkali metals are poorly soluble in hydrocarbons, a consequence of their more ionic nature. The heavier alkali metal compounds, as well as alkyllithiums, are soluble in more polar solvents such as ethers. The use of most of the alkali metal compounds, especially, the more ionic ones, in ether solvents is somewhat limited by their reactivity toward ethers. The problem is overcome by working below ambient temperatures and/or using less reactive (i.e., resonance-stabilized) anions as in benzylpotassium, cumylcesium and diphenylmethyllithium. 

Many compounds in nature, particularly compounds made of Ccirbon, hydrogen, and oxygen, are composed of atoms that occur in numbers that are multiples of their empirical formula. In other words, their empirical formulas don t reflect the actual numbers of atoms within them instead, they reflect only the ratios of those atoms. What a nuisance Fortunately, this is an old nuisance, so chemists have devised a means to deal with it. To account for these annoying types of compounds, chemists are Ccireful to differentiate between an empirical formula and a moleculcir formula. A molecular formula uses subscripts that report the actual number of each type of atom in a molecule of the compound (a formula unit accomplishes the same thing for ionic compounds). 

Water and ammonia, therefore, behave similarly in the formation of substitution compounds, and there is gradation from ammino-salt through aquo-ammino- to purely aquo- or hydrated salt further, the entrance of water in place of ammonia does not alter the ionic nature of the acidic radicles outside the complex. 

Long (81) showed that the complex from biscyclopentadienyltitanium dichloride and methylaluminum chloride or a simply derived product from it, was an active ethylene polymerization catalyst. There have been a number of attempts to determine the exact nature of initiation in polyethylene. However, by any techniques available until now, it has not been possible to determine the actual ionic nature of the active catalyst which polymerizes ethylene. Karapinka and Carrick (82) studied the polymerization of ethylene with biscyclopentadienyltitanium dichloride and various alkylaluminum compounds. They found that the alkyl group exchanged so readily between the aluminum and titanium, that the location of the initiating site could not be determined. All that could be concluded was that an ethyl group initiated the polymerization more easily than the phenyl. 

The chemical bond between the superoxide ion, OJ, and the metal ion is ionic in nature. Melting points of potassium, rubidium and cesium superoxide have been determined, and in keeping with the ionic nature of the compounds, the melting temperatures arc high, in the order of 400°C. 

Another point which needs to be clarified from the start is the nomenclature of metalated silanes We will frequently use the term silyl anion in this chapter when we talk about metalated silanes. Although the term anion defines, literally taken, an ionic compound, this expression, when used by us, does not necessarily imply that the compound in question is of ionic nature, but covers, as well, in analogy to the use of the term carbanion , silicon compounds with a polarized covalent silicon-metal bond. 

For neutral organic compounds, in soils having a low clay/organic carbon ratio, sorption coefficients tend to increase as the hydrophobicity of the compound increases. Aqueous solubility or octanol/ water partition coefficients often are used as indicators of a compound s hydrophobicity. An increase in polarity, number of functional groups, and ionic nature of the chemical will increase the number of potential sorption mechanisms for a given chemical (Garbarini and Lion, 1985). For ionizable compounds, pKa is of particular importance because it determines the dominant form of a chemical at the specific environmental pH. 

A mixed convention will be used in this chapter as an aid to indicate whether a given compound may be written in the ionized form. We will use Na+Cl-, Ba2+(NO )2, and similar notation, to indicate that compounds are ionic. Naturally, the compounds could be expressed by the molecular formulas, NaCl and Ba(N03)2, which works well for those who are intimately familiar with the solubility rules. We are not presenting the solubility rules since we prefer to concentrate on balancing the equations without having the distraction of investigating the solubility rules at the same time. 

The term semi-clathrate refers to solid inclusion compounds where, in addition to non-bonded, clathrate interactions, there is a contribution of chemical bonding. In the example used above, this chemical contribution is of ionic nature fluoride anion from the ammonium salt is incorporated into the water host framework linked via hydrogen bonds. Thus, the host has anionic character and guest-host interactions have ionic component. 

Another important feature of the extracoordinate silicon compounds (Scheme 7.14) is the increase in natural atomic charge at the central atom compared to the tetracoordinate precursors [69]. The counter-intuitive increase in the positive charge on silicon, which becomes even more substantial in the case of anionic nucleophiles, such as F , is compensated by a more negative character of the surrounding groups (X), and this results in an enhanced ionic nature of the Si-X bond. This polarization then favors intermolecular charge-dipole interaction, which results in an increased Lewis acidity of the hypercoordinate silicon [70]. 

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