Bonding power

The boranes are electron-deficient compounds (Section 3.8) we cannot write valid Lewis structures for them, because too few electrons are available. For instance, there are 8 atoms in diborane, so we need at least 7 bonds however, there are only 12 valence electrons, and so we can form at most 6 electron-pair bonds. In molecular orbital theory, these electron pairs are regarded as delocalized over the entire molecule, and their bonding power is shared by several atoms. In diborane, for instance, a single electron pair is delocalized over a B—H—B unit. It binds all three atoms together with bond order of 4 for each of the B—H bridging bonds. The molecule has two such bridging three-center bonds (9). 

With the Pa2 dimer, we have reached the maximum bonding power among the actinide dimers. In U2 the bond energy decreases and the bond length increases, which is from the increased stabilization of the 5f orbitals and the corresponding destabilization of 6d. Large transfer of electrons from... 

At a concentration of 5 to 25 wt %, increased the effective kill-life of the lindane spray up to 10 times. May have been used in chlordane and BHC insecticide formulations. In polyvinyl acetate emsulsions to impart strong bonding power in adhesives (Monsanto, 1960). 

In this chapter, we review the key properties of a central structural feature in hydrogen bonding powered enzymatic catalysis-the oxyanion hole. 

In the mathematical theory of networks valence is defined as the number of links terminating at a node, and it was in this sense that the term was introduced into chemistry. However, chemists were later forced to distinguish between a chemical valence (bonding power) and a coordinative valence (number of bonds). They chose to keep the term valence for the chemical valence and introduced the term coordination number for the coordinative valence. This book follows the chemical convention. The term valence is always used in the sense of bonding power unless otherwise stated, and coordination number is used to indicate the number of bonds. 

As the bonding power of catalyst to the vital reactant in the rds increases in the series of catalysts, 0 will also increase and hence the rate of production per unit area. 

This increase will continue as one moves through the series of catalysts, always with increasing bonding power (hence increasing 0 in the steady state). However, as 0 increases, the free surface available for adsorption decreases. One has to account for this in the expression for the rate with a (1 - 0) term, so that an expression for the reaction rate would be proportional both to 0 and to (1 - 0). Now, were this clash of increasing 0 (good) and decreasing availability for adsorption from the solution (bad) the only factor, then... 

Pauling and Sherman, loc. cit. (4). Calculations of the bonding power of 2 -2p hybrid orbitals have been reported also by R. S. Mulliken, J. Chem. Phys. 19, 900, 912 (1951). C. A. Coulson and G. R. Lester, Trans. Faraday Soc. 51, 1605 (1955), have made calculations for excited states of the hydrogen molecule-ion that agree reasonably well with the postulate that the strength S of an orbital determines its bond-forming power. 

The acid strengths in the sequence Si(OH)4, PO(OH)j, SOt(OH), ClOa(OH) can be discussed qualitatively in a simple way. The bonds from the central atoms have the strengths 1, , f, and , respectively, leaving each oxygen atom with further bonding power of 1, f, , and J, respectively, for hydrogen. In consequence, silicic acid is a very weak acid, phosphoric acid is a weak acid, sulfuric acid is a strong acid, and... 

In this case the antibonding power of the (or u)2 orbital cancels the bonding power of the (cjij) orbital with the well known result that the molecule is not formed. 

Values for the maximum tt bond number are given as /3 for carbon, y/2 for nitrogen, and 1 for oxygen see Ref. 70). The unused TT-bonding power obtained by use of Equation 11.5 makes atoms with high values of fr very susceptible to attack, particularly by free radicals. ... 

Mulliken, R. S. (1951) Overlap and bonding power of 2s,2p hybrid orbitals. J. Chem. Phys., 19, 900-912. 

The purest as well as the strongest clays are probably the so-called ball clays, the plasticity and bonding power of which is reinforced by the presence of organic matter. This type of clay seems to be preferred in the manufacture of graphite crucibles, and other special refractories. 

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