Bonding bond distances, table

The X—N bond distances (Tables 4-8) in XH3NNN and XH3NCZ show the azide being consistently the larger. This is probably because of the smaller XNN bend angle which can introduce steric repulsion effects, and shows that structures with X=N double... 

Both PNDO and MINDO/1 thus use standard values of bond distances (Table 9). In the MINDO/2 program however, Dewar and Hasel-bach 35> seem to have solved the problem outlined above. Their calculation provide both good heats of formation and bond distance for Hydrocarbons and Nitrogen and Oxygen heteromolecules, thus opening a new dimension for application of their method. 

The heterobimetallic compounds 79-83 comprise Ag(I)-Sn(II) covalent bonds, with similar Ag—Sn bonding distances (Table 2.11.3). In particular, compounds 79 and 80 give dimeric arrangements, while in for 81-83, the use of silver fluorinated tris(pyrazolyl)borates and tin(II) N-alkyl-2-(alkylamino)troponiminates allow the isolation of monomeric compounds. 

The connectivity information can be given either implicitly by approximating bonding distances between the atoms, or explicitly by a connection table (bond list as shown in Figure 2-20 and 2-25. 

The bond dipoles m Table 1 3 depend on the difference m electronegativity of the bonded atoms and on the bond distance The polarity of a C—H bond is relatively low substantially less than a C—O bond for example Don t lose sight of an even more important difference between a C—H bond and a C—O bond and that is the direction of the dipole moment In a C—H bond the electrons are drawn away from H toward C In a C—O bond electrons are drawn from C toward O As we 11 see m later chap ters the kinds of reactions that a substance undergoes can often be related to the size and direction of key bond dipoles... 

Bond Distances, Bond Angles, and Bond Energies in Ethane, Ethene, and Ethyne (Table 9 1, p 342) Stmctures of a-Ammo Acids (Table 27 1, pp 1054-1055)... 

Bismuthides. Many intermetaUic compounds of bismuth with alkafl metals and alkaline earth metals have the expected formulas M Bi and M Bi, respectively. These compounds ate not saltlike but have high coordination numbers, interatomic distances similar to those found in metals, and metallic electrical conductivities. They dissolve to some extent in molten salts (eg, NaCl—Nal) to form solutions that have been interpreted from cryoscopic data as containing some Bi . Both the alkafl and alkaline earth metals form another series of alloylike bismuth compounds that become superconducting at low temperatures (Table 1). The MBi compounds are particularly noteworthy as having extremely short bond distances between the alkafl metal atoms. 

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