Inferences on chemical reactions

Hans-Beat Biirgi and Jack D. Dunitz and their co-workers have postulated that if the mode of restructuring of compounds as a result of a chemical reaction is known, then a study of the detailed geometries of 

FIGURE 18.7. Reaction of ammonia with 4-chlorobenzoic acid to give ammonium 4-chlorobenzoate. 

To relate bond lengths to their bond number n (single, double, or triple) Pauling suggested a relationship, where d is the observed interatomic distance and the assigned single bond distance. The equation 

FIGURE 18.9. Example of an Sjv2 reaction. Az = displacement of B from the plane through the three A atoms (Ref. 34). 

No compound with five-coordinate carbon as the central atom has yet been crystallized. Burgi, however, has studied a series of trigonal bipyramidal complexes of divalent cadmium with three equatorial sulfur ligands and with axial ligands iodide, hydroxyl, or sulfur groups ( Y and X). 

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