Anion A negative ion

Angular momentum quantum number ( ) the quantum number relating to the shape of an atomic orbital, which can assume any integral value from 0 to n — 1 for each value of n. (12.9) Anion a negative ion. (2.7)... 

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

Anion A negatively charged ion in an electrolyte solution, attracted to the anode under the influence of a difference in electrical potential. Chloride is an anion. Anion exchange capacity Sum total of exchangeable anions that a soil can adsorb. Expressed as centimoles of negative charge per kilogram of soil. 

Anion a negatively charged ion it migrates to the anode of a galvanic or voltaic cell. 

The differences in radii between atoms and ions can be explained quite simply. A cation is smaller than the corresponding metal atom because the excess of protons in the ion draws the outer electrons in closer to the nucleus. In contrast, an extra electron in an anion adds to the repulsion between outer electrons, making a negative ion larger than the corresponding nonmetal atom. 

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... 

The same reasoning indicates that the absence of a negative ion will leave a positive effective charge relative to a normal site occupied by a negative ion. A vacancy at a chloride ion (Cl-) site is positively charged relative to the normal situation prevailing at an anion site in the crystal. Using Eq. (1.1) ... 

Ionic polymerisation can be categorised into two classes, (i) Cationic polymerisation and (ii) Anionic polymerisation, depending upon the nature of ions used for the initiation of polymerisation. The cationic polymerisation refers to the process in which a positive ion is used for initiation. When a negative ion is used for initiation of polymerisation, then process is referred to as anionic polymerisation. 

In anionic polymerisation p-electrons of the monomers are attached by negatively charged ion, an anion, so the anionic polymerisation is initiated by a negative ion or anion. An anion generates a carbanion on reaction with a monomer and carbonion is an active centre which propagates the reaction. 

Ionic compounds result from the combination of a positive ion known as a cation and a negative ion called an anion. Salt is an ionic compound in which sodium cations and chloride anions chemically combined. Molecular compounds contain discrete molecular units. Molecular units or molecules are the smallest unit of a molecular compound. Atoms in a compound are held together by covalent bonds. Bonds dictate how atoms are held together in a compound or molecule, but for now, just think of ionic compounds as compounds composed of ions, and molecular compounds as compounds composed of molecules. Sugar, water, and carbon dioxide are examples of molecular compounds. 

Turning to the pulse radiolysis data for further information, it is fairly obvious that any attempt to explain the radiation-induced polymerization of a-methylstyrene on the basis of a single ionic species, be it a positive or a negative ion, is faulted by the data. Certainly several species are formed in detectable quantities. It is unfortunate that they all absorb in essentially the same region of the spectrum, but this is not unexpected (11). What it means, however, is that neither identities nor concentration can be established solely on the basis of the spectrum that one obtains. Thus, it would appear that ascribing the spectrum of a-methylstyrene to the radical anion, as Hirota has done (13), is at best an oversimplification. 

One effect important to mention here is the effect of the electric field, X, which can be as strong as 10 V cm, on the shape of the adsorbing species. The effect of this electrical field on the ion can be understood in the following way The electrical field is directed perpendicularly to the electrode, toward the solution, as shown in Fig. 6.96. It can be considered equivalent to having an electrical force acting on the adsorbed ion. [f we consider a negative ion (anion) adsorbed on the surface, this force is given by... 

Prof. Schlag ( ZEKE Spectroscopy, this volume) has introduced a new sequential technique of ZEKE spectroscopy In the first step, a negative ion M is photoionized, yielding the neutral core M of the excited Rydberg state of the anion M. In the second step, M is further photoionized, yielding the cationic core M+ of the excited Rydberg state of the neutral molecule M. The overall sequence is thus... 

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