Lithium bond dissociation energies

From this value and known C—H bond dissociation energies, pK values can be calculated. The electrochemical measurements can be made on halides or on alkyl-lithium compounds. This type of approach has some significant uncertainties but nevertheless can provide a least a semiquantitative estimate of acidities of very weakly acidic hydrocarbons. The pK for isobutane obtained in this way is 71. The necessary electrochemical measurements cannot be made directly for methane, but an extrapolation from toluene and diphenylmethane leads to a range of 52-62 for the pK of methane. ... 

Nitrogen is a diatomic molecule, which is effectively triple-bonded and has a high dissociation energy (940 kj mol" ). It is therefore inert and it only reacts readily with lithium and other highly electropositive elements. The direct combination of nitrogen and hydrogen occurs at elevated temperatures and pressures (400-600°C, 100 atmospheres) and is the basis of the industrially important Haber process for the manufacture of ammonia. 

Table 9.1. Dissociation energies and bond distances in gaseous homonuclear diatomic species (charged or uncharged) formed from the second period elements from lithium to neon. ...

As a diatomic molecule nitrogen is effectively triple-bonded and has a high dissociation energy (940 kj moH). It is therefore relatively inert at room temperature and reacts readily only with lithium... 

Armentrout and Rogers also suggest more suitable anchor points for the LCA scale, e.g. the lithium cation bond energies to methanol or dimethyl ether. They further examined the kinetic energy dependences of the CID of Li+—ROH with and reported that the dominant dissociation process in all cases is the loss of alcohol. The thresholds for Li+—ROH dissociations were determined and converted to enthalpies and free energies at 298 and 373 K for comparison with previous equihbrium data on these systems. LCA values at 298 K for a series of alcohols are summarized in Table 3. The experimental results are compared with enthalpies of binding (PA) at 298 K (Figure 2) and a linear correlation between the LCA and the PA is found. 

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