Bond yield measure types

Simple amides of this type are the bis(trimethylsilyl)amides M[N(SiMe3)2]2 (M = Cd and Hg) the essential thermodynamic data of which have been determined in calorimetric measurements of the heats of hydrolysis in dilute H2S04.146 Evaluation of the measured data yielded the standard enthalpies of formation AH° = —854(21)kJmoU1 and —834(9)kJmol-1 for M =Cd and Hg, respectively. Using subsidiary data, the average thermochemical bond energies E—(Cd—N) 144 and E(Hg—N) 108 kJ mol-1 were also obtained, i.e., the Cd—N bonds are considerably stronger than the Hg—N bonds. 

It is very difficult to obtain values for the intrinsic hardnesses of silicate and related types of glass. Therefore, no attempts at quantitative analyses will be made here. A semi-empirical method has been proposed by Yamane and Mackenzie (1974) based on the geometric mean of bond strength relative to silica, shear modulus, and bulk modulus. For 50 silicate glasses it yields estimates within ten percent of measured values, and for a few non-silicate glasses it is quite successful, as Figure 14.2 indicates. 

The reaction of these yellow square-planar complexes with small molecules was shown to yield stable five-co-ordinate adducts of the type [RhClLA] (A = BF3, CO, HgClj, SO2, O2, S2, H, NO, or N2ph ). I.r. measurements confirmed the presence of co-ordinated BF3, and supported symmetrical Tt-bonding of the O2 and S2 complexes (28). The greater stability of these adducts... 

Methods for the detection of placement and quantitation of Si-H, Si-OH and Si-0 groups in molecular weight components of silicones of the polydimethylsiloxane type have been developed using SEC-IR and SEC-UV on-line techniques. In the case of silanols, problems with partial hydrogen bonding were overcome by use of 1,4-dioxane mobile phase. For phenyl groups, methylene chloride was effective for qualitative measurements and THF yielded quantitative results at high sensitivity. 

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