Nitrogen electron affinity

Table 2.6 shows the electron affinities, for the addition of one electron to elements in Periods 2 and 3. Energy is evolved by many atoms when they accept electrons. In the cases in which energy is absorbed it will be noted that the new electron enters either a previously unoccupied orbital or a half-filled orbital thus in beryllium or magnesium the new electron enters the p orbital, and in nitrogen electron-pairing in the p orbitals is necessary. 

The XeF+ cation forms Lewis acid—base adduct cations containing N—Xe—F linkages with nitrogen bases that are resistant to oxidation by the strongly oxidizing XeF+ cation having an estimated electron affinity of the XeF+ cation of 10.9 eV (12). The thermally unstable colorless salt,... 

Optical absorption measurements give band-gap data for cubic sihcon carbide as 2.2 eV and for the a-form as 2.86 eV at 300 K (55). In the region of low absorption coefficients, optical transitions are indirect whereas direct transitions predominate for quantum energies above 6 eV. The electron affinity is about 4 eV. The electronic bonding in sihcon carbide is considered to be predominantiy covalent in nature, but with some ionic character (55). In a Raman scattering study of vahey-orbit transitions in 6H-sihcon carbide, three electron transitions were observed, one for each of the inequivalent nitrogen donor sites in the sihcon carbide lattice (56). The donor ionization energy for the three sites had values of 0.105, 0.140, and 0.143 eV (57). 

The polarity of the C—-OH bond, i.e., the basicity of the carbinol-amine, depends on its structure, particularly on the stability of the ring system (degree of aromatic character), and the electron affinity of the substituents on nitrogen and carbon. Of course, external factors also play an important role in the equilibrium temperature, polarity of the solvent, and presence or absence of catalysts (the solvent can also act as a catalyst). 

The electron affinity of carbon is greater than that of nitrogen indeed, the latter is negative. Suggest a reason for this observation. 

Which element of each of the following pairs has the higher electron affinity (a) oxygen or fluorine (b) nitrogen or carbon (c) chlorine or bromine (d) lithium or sodium ... 

Hydrogen bonds are formed to some extent by oxygen ((H20)x, ice, etc.) and perhaps also in some cases by nitrogen. The electrostatic structure for the hydrogen bond explains the observation that only these atoms of high electron affinity form such bonds, a fact for which no explanation was given by the older conception. It is of interest that there is considerable... 

Pyridine.—We shall begin the discussion with pyridine rather than with a substituted benzene, since it offers a particularly simple N example, in which only the inductive effect is operative. We number the atoms I in order, beginning with nitrogen. Then <5j, which takes into account the electron affinity of the nitrogen atom, will be positive in sign, and of the order of magnitude of... 

Phenyltrimethylammonium Ion, N+(CH3)S-CaHe.—In this ion, as in toluene, we ignore the electrons involved in bonds from nitrogen to the attached groups, and consider only the inductive effect. The positive charge on the nitrogen atom increases its electron affinity to a value still greater than that for neutral nitrogen, so that we... 

By introducing reasonable values (about 2 for nitrogen, 4 for oxygen) for the electron affinity parameter relative to carbon, 8, and for the induced electron affinity for adjacent atoms (32/8i = Vio), we have shown that the calculated permanent charge distributions for pyridine, toluene, phenyltrimethylammonium ion, nitrobenzene, benzoic acid, benzaldehyde, acetophenone, benzo-nitrile, furan, thiophene, pyrrole, aniline, and phenol can be satisfactorily correlated qualitatively with the observed positions and rates of substitution. For naphthalene and the halogen benzenes this calculation does not lead to results... 

The reaction of eh with H2 is very slow ( 105 M-1s-1), due to a positive free energy barrier. Nitrogen has negative electron affinity it is unreactive toward eh. 02 has a high electron affinity, and it reacts with eh with a diffusion-controlled rate (see Table 6.6). The immediate product of the reaction, 02- or its acidic form HOz, reacts further with itself, giving H202and Or... 

The electron affinity of nitrogen is out of line with those of other atoms in the same period because it has a stable half-filled shell. 

Whereas nitrogen has an electron affinity that is approximately zero, phosphorus has a value greater than zero even though it also has a half-filled outer shell. The effect of a half-filled... 

Amines possess a pair of p-electrons on the nitrogen atom. The nitrogen atom has a low electron affinity in comparison with oxygen. Therefore, amine can be the electron donor reactant in a charge-transfer complex (CTC) in association with oxygen-containing molecules and radicals. It will be shown that the formation of CTC complexes of amines with peroxyl radicals is important in the low-temperature oxidation of amines. 

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