Bond strength hydrogen-element

Since the hydrogen-element bond energy decreases from sulphur to tellurium they are stronger acids than hydrogen sulphide in aqueous solution but are still classified as weak acids—similar change in acid strength is observed for Group Vll hydrides. 

FIGURE 2.19 The dissociation energies for bonds between hydrogen and the p-block elements. The bond strengths decrease down each group as the atoms increase in size. 

Describe the trend in acidity of the binary hydrogen compounds of the Group 16/VI elements and account for the trend in terms of bond strength. 

HYDROGEN-ELEMENT BOND STRENGTH (KCAL.MOLE-1)... 

Fig. 4. Experimental reactivation energies for each donor element versus hydrogen-donor species bond strength. The formation of hydrogen-donor bonds is supported by the good correlation between these two parameters (Pearton et al., 1986).

Because of the lower metal-carbon and metal-hydrogen bond strength, organolead hydrides are particularly unstable species and represent the least stable of those of the group 14 elements. Triorganolead hydrides are obtained at low temperatures by reduction of the halides with LiAlH4 (equation 45), but they decompose at 0 °C. 

Bond strengths help to explain the relative stabilities within families of compounds. For example, the average strength of the bond between hydrogen and a Group 14 element decreases down the group, from carbon (412 kj-mol-1) to lead (205 kjTnol-1), as shown in Fig. 2.14. This... 

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