Carbon-nitrogen triple bond Table

This table is a partial listing of GC values available from the original Domalski-Hearing tables. Table-specific nomenclature Cd = carbon with double bond Ct = carbon with triple bond Cb = carbon in benzene ring Ca = allenic carbon corr = correction term Cbf = fused benzene ring Na = azo nitrogen Ni = imino nitrogen. 

Revised Values of Double-Bond Covalent Radii.—This investigation has led to the value 1.34 A. for the carbon-carbon double-bond distance, 0.04 A. less than the value provided by the table of covalent radii.111 4 Five years ago, when this table was extended to multiple bonds, there were few reliable experimental data on which the selected values for double-bond and triple-bond radii could be based. The single-bond radii were obtained -from the study of a large number of interatomic distances found experimentally by crystal-structure and spectroscopic methods. The spectroscopic value of the triple-bond radius of nitrogen (in N2) was found to bear the ratio 0.79 to the single-bond radius, and this ratio was as-... 

The new carbon-carbon double-bond distance corresponds to the value 0.87 for the double-bond factor. Moreover, there are now available three accurately known triple-bond distances 1.204 for C=C in acetylene, 1.154 A. for C=N in hydrogen cyanide, and 1.094 for N==N in the nitrogen molecule, whereas five years ago only the last was known. The ratios of these distances to the corresponding sums of single-bond radii are 0.782, 0.785, and 0.781, respectively. We accordingly now select 0.78 as the value of the triple-bond factor. Revised covalent radii26 for first-row atoms are given in Table XV. 

Whereas carbon is able to form stable (p-p) double and triple bonds with carbon itself, nitrogen and oxygen, leading to coordination numbers 2 and 3 at the carbon atom, silicon cannot build up such bonds (compare Table 2). Although the existence of monomeric species such as SiO and SiNH has been established under specific conditions, and (p-p)ff bonded intermediates have been postulated in a number of... 

The geometries are given in Table 8. Since carbon, nitrogen, and oxygen have very similar covalent radii (0.77, 0.74, 0.73A) it is easy to compare bond lengths. We see that the N =N triple bonds tend to be shorter than in N5 while CsN triple bonds tend to be longer than the difference in covalent radii suggests. 

C3H3N3 and also the tetrazines C2H2N4 are very stable compounds, pentazine CHN5 and hexazine N6, a polymer of nitrogen, do not exist. This is not due to the instability of these molecules as such but to the very special stability of the triple bond in nitrogen and in HCN, compared with the corresponding single and double bonds, while this holds to a much smaller extent for the triple carbon-carbon bond (Table 18). 

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