Boranes interatomic distances

In the hands of Lipscomb and others 76,143, 145a, 153,189, 190), such localized bond schemes, particularly when obtained via self-consistent field (SCF) molecular orbital (MO) treatments, have proved particularly valuable for rationalizing the shapes and interatomic distances and estimating the charge distribution in many higher boranes. 

In a oloso-cluster species such as a borane anion B H , in which the n skeletal atoms are held together by (n -h 1) bond pairs, the interatomic distances—the edge lengths of the B polyhedron—can be rationalized if one regards the skeletal atoms as held together by a network of... 

Yet other factors influence the interatomic distances in nido- and orocAwo-boranes, for example whether the polyhedron edges border the open face of the polyhedral fragment, and if so whether they are sewn... 

Fig. 31. Boron-boron interatomic distances in boranes with skeletons based on an octahedron closo-BgHg ", nido-BsHg, and arachno- iRio.

The C—C and C—B interatomic distances in carboranes can also be related to the coordination numbers of the skeletal atoms. Two factors tend to make these distances shorter than the B —B distances in comparable boranes the preference of the carbon atoms for sites of low coordination number and the greater electronegativity of carbon than boron, which increases the electron density in the region of the carbon atoms and so strengthens the bonds that they form. Table IX lists some C—C distances for closo- and wido-carboranes 13, 20, 21, 26, 98,121,168) and metal-acetylene 50, 58,112) complexes, relating them... 

One of the lasting practical results of treating metals in this model has been the tabulation of atomic radii and interatomic distances in metals [39-42]. Another interesting application of the unsynchronized-resonating-covalent-bond-theory of metal is its use in the elucidation of the to the structure and properties of elemental boron and the boranes [43]. 

---