Ions: anions

Molecular Interactions. Various polysaccharides readily associate with other substances, including bile acids and cholesterol, proteins, small organic molecules, inorganic salts, and ions. Anionic polysaccharides form salts and chelate complexes with cations some neutral polysaccharides form complexes with inorganic salts and some interactions are stmcture specific. Starch amylose and the linear branches of amylopectin form inclusion complexes with several classes of polar molecules, including fatty acids, glycerides, alcohols, esters, ketones, and iodine/iodide. The absorbed molecule occupies the cavity of the amylose helix, which has the capacity to expand somewhat to accommodate larger molecules. The starch—Hpid complex is important in food systems. Whether similar inclusion complexes can form with any of the dietary fiber components is not known. 

Anion A negatively charged particle or ion. Anion interchange The displacement of one negatively charged particle by another on an anion-exchange material. 

Nonmetal atoms form negative ions (anions—pronounced AN-i-ons) by gaining electrons. Consider, for example, what happens when atoms of the nonmetals chlorine and oxygen acquire electrons ... 

NEGATIVE IONS (Anions) POSITIVE IONS. . FORM (Cations) COMPOUNDS WITH solubility ... 

POSITIVE IONS (cations) negative ions (anions) ... 

Bulk structures of oxides are best described by assuming that they are made up of positive metal ions (cations) and negative O ions (anions). Locally the major structural feature is that cations are surrounded by O ions and oxygen by cations, leading to a bulk structure that is largely determined by the stoichiometry. The ions are, in almost all oxides, larger than the metal cation. It does not exist in isolated form but is stabilized by the surrounding positive metal ions. 

There are basically two types of collector molecules ionizing and nonionizing compounds. The former dissociates into ions in water, while the latter does not. Ionizing collectors are classified in accordance with the type of ion (anion or cation) that causes the water-repellent effect in water. 

The first example relates dissolution of zinc metal. This pertains to Figure 5.2 (A) which provides the answer for conditions of dissolution. The dissolution of a metal is electrochemical in nature and, as the potential for the dissolution of zinc is more negative than both of the above reactions, each of them can serve as a cathodic process to support the anodic dissolution of zinc. It may be seen from Figure 5.2 (A) that solubilization is favorably disposed below a pFF of about 6.9 with the production of Zn2+ ions (cations) and beyond a pH of about 13.4 with the formation ZnO ions (anions). 

Study of the solutions of monovalent ions [Anions, Argentous and Mercurous]... 

An electrically charged atom or group of atoms. An atom which loses an electron becomes a positive ion (cation) and one which gains an electron becomes a negative ion (anion). In electrolysis anions are attracted to the anode and cations to the cathode, lonomer... 

Most studies of micellar systems have been carried out on synthetic surfactants where the polar or ionic head group may be cationic, e.g. an ammonium or pyridinium ion, anionic, e.g. a carboxylate, sulfate or sulfonate ion, non-ionic, e.g. hydroxy-compound, or zwitterionic, e.g. an amine oxide or a carboxylate or sulfonate betaine. Surfactants are often given trivial or trade names, and abbreviations based on either trivial or systematic names are freely used (Fendler and Fendler, 1975). Many commercial surfactants are mixtures so that purity can be a major problem. In addition, some surfactants, e.g. monoalkyl sulfates, decompose slowly in aqueous solution. Some examples of surfactants are given in Table 1, together with values of the critical micelle concentration, cmc. This is the surfactant concentration at the onset of micellization (Mukerjee and Mysels, 1970) and can therefore be taken to be the maximum concentration of monomeric surfactant in a solution (Menger and Portnoy, 1967). Its value is related to the change of free energy on micellization (Fendler and Fendler, 1975 Lindman and Wennerstrom, 1980). 

The attractions between positive ions (cations) and negative ions (anions) are strong, and ionic compounds have a giant lattice stmcture. 

There is no necessary relation between the electrical properties of the polymer cation, its anion, and the corresponding ion-pair, and those of the ions present in the solution before the isobutene is added. In fact, since the planar tertiary carbonium ion at the growing end of the polymer chain is much smaller than any cation (except the improbable A1C12+) derivable from aluminium chloride, the dissociation constant of the carbonium ion - anion pair, whatever the anion, must be much smaller than that of the ion-pairs existing in the catalytic solutions before the addition of the monomer. 

Hehre and co-workers (DeFrees et al., 1977, 1979a) have published both experimental and theoretical evidence in support of negative ion (anionic) hyperconjugation. These workers determined the free energies for the gas-phase hydron3 transfer equilibria (31), (32) and (33) by pulsed ion cyclotron resonance spectroscopy (Wolf et al., 1976). These equilibria, which involve the gas-phase formation of a methylamino, a methoxy and a thiomethoxy anion, all lie to the right, i.e. the formation of the isotopically light anion is favoured. These results were rationalized in terms of the MO... 

The ionic divide , at group 18, separates elements at its immediate right, which easily form positive ions (cations), from those (halogens, chalcogens) which easily form negative ions (anions). 

Perchlorate and nitrate, as well as the halides, are less mobile relative to their size than the tetrafluoroborate and hexafluorophosphate ions. Anions that lie below the upper curve in Fig. 3 appear to undergo interaction with acetonitrile to a greater extent than would be expected on the basis of simple charge-dipole interaction, but the nature of this interaction is difficult to postulate. The fluoro ions should less likely undergo specific interactions. Because the differences in mobilities are not great, however, extensive speculation is unwarranted. 

In the intercalation reactions, ions (anions X or cations M+) penetrate into the van der Waals gaps between the ordered carbon layers resulting in the enlargement of their inter-layer distance [23,24]. The corresponding charges are conducted by carbon and accepted into the carbon host lattice. 

Ionic solids are also called salts. Salts are composed of atoms held together by ionic bonds. These bonds are the result of electrostatic attractions between positively charged ions (cations ) and negatively charged ions (anions). The force of electrostatic attraction is inversely related to the square of the distance of separation of the ions (Eq. 2.1). 

First consider the system in which no diffusion potential is formed in the membrane. The membrane potential is then determined by the conditions at the membrane/aqueous electrolyte solution boundary. In the simplest situation, a salt of a monovalent ion-exchanger ion, anion A", with monovalent determinand cation J is dissolved in the membrane. In order for this system to be the basis for a usable ISE with Nemstian response to the determinand ion in a sufficiently broad activity interval, it is necessary that the distribution coefficient kj be... 

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