Table 5. Differences (Δ) of CX–N and C6–N Bond Lengths (in Å) between Formamide (ε = 108.94) and the Gas Phase (ε = 1)a.
| X = NH2 |
X = NO2 |
|||||
|---|---|---|---|---|---|---|
| ΔCX–N | ΔC6–N | ΔCX–N | ΔC6–N | type of proximity X | ||
| 9H | C2 | 0.0011 | –0.0025 | –0.0099 | –0.0065 | I |
| 7H | 0.0035 | –0.0188 | 0.0122 | –0.0253 | I | |
| 3H | –0.0199 | –0.0042 | –0.0037 | –0.0075 | II | |
| 1H | –0.0204 | –0.0274 | –0.0074 | –0.0198 | II | |
| 9H | C8 | –0.0141 | –0.0003 | –0.0118 | –0.0079 | II |
| 7H | –0.0148 | –0.0145 | –0.0121 | –0.0243 | II | |
| 3H | 0.0031 | –0.0035 | –0.0206 | –0.0086 | I | |
| 1H | 0.0085 | –0.0252 | –0.0215 | –0.0248 | I | |
a
In the case of 7H C2–NO2, positive change (marked in italics) is associated with a rotation of the NO2 group and was not considered in average values discussed above.