Hydrogen electron affinity

Association Complexes. The unshared electron pairs of the ether oxygens, which give the polymer strong hydrogen bonding affinity, can also take part in association reactions with a variety of monomeric and polymeric electron acceptors (40,41). These include poly(acryhc acid), poly(methacryhc acid), copolymers of maleic and acryflc acids, tannic acid, naphthoHc and phenoHc compounds, as well as urea and thiourea (42—47). 

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... 

Hydrogen has a substantial electron affinity, which shows that we might expect compounds containing H to be formed. 

A novel form of Y HX hydrogen bonding49 results when the Lewis base Y is itself a hydride ion (H-). Because the electron affinity of a hydrogen atom is extremely weak (21 kcal mol-1), the H- ion is among the most weakly bound and diffuse anionic species known, and hence a powerful Lewis base. In this case, the H - -HX complex can be referred to as a dihydrogen bond 50 to denote the unusual H-bonding between hydrogen atoms. A water complex of this type was... 

We consider two cases (see Fig. A.13). First, the metal has a work function that is between electron affinity (the energy of the o -level) and the ionization potential (the energy of the o-level) of the molecule. Upon adsorption, the levels broaden. However, the occupation of the adsorbate levels remains as in the free molecule. This situation represents a rather extreme case in which the intramolecular bond of the adsorbate molecule stays about as strong as in the gas phase. The other extreme occurs if both the a-level and the o -1evel fall below the Fermi level of the metal. Because the antibonding G -level is filled with electrons from the metal, the intramolecular bond breaks. This is the case for hydrogen adsorption on many metals. Thus, a low work function of the metal and a high electron affinity of the adsorbed molecule are favorable for dissociative adsorption. 

Electron Affinity of Hydrogen, Deuterium, and Tritium Atoms Obtained with 300 Explicitly Correlated Gaussian Functions ... 

Ervin et al. [27] have determined the electron affinity of the acetylide radical, HC = C-, to be equal to 2.969 + 0.010 eV and the enthalpy of the acid dissociation of acetylene in the gas phase to be equal to 377.8 + 0.6 Kcal mol Use these data, together with the ionization potential of the hydrogen atom, 13.595 eV, to calculate the enthalpy for the dissociation of the CH bond in acetylene. The ionization potentials are properly applied at 0 K, but a good approximation is to assume that they are equal to enthalpy changes at 298.15 K, the temperature at which the enthalpy of the acid dissociation was measured. 

The bond energy of the H-H bond is 431 kJ/mol. Electron affinity of hydrogen is low (-72 kJ/mol), where hydrogen reacts in this marmer only with the most reactive metals. The ionization potential of hydrogen is relatively high (1312 kJ/mol). Hydrogen bums with a veiy hot flame and explosion in air ... 

---