Knowledge Bank

The infrared spectra of the N-14 and N-15 isotopic species of $NO2Cl$ and $NO2F$ have been investigated in the vapor and solid states. Assignments of two fundamental frequencies in both halides have been changed from those of previous studies. The original assignments of $\nu 3$ and $\nu 5$ have been reversed in the case of $NO2Cl$ and a band at $460cm-1$ in $NO2F$ which had been attributed to $\nu 3$ was shown to originate from an impurity. New sets of force constants using both the Valence Force Field and the Urey-Bradley Force Field were calculated. $NO2Cl$ was found to be particularly favorable for normal coordinate analysis and unique force constants were determined.