Infrared Spectrum and Force Constants of the Nitrite Ion

Abstract

The infrared spectra of the following compounds have been investigated: microcrystalline NaNO2, KNO2, and AgNO2; and aqueous solutions of NaNO2 and KNO2. The spectra of N15-labeled compounds have also been obtained. The spectrum of the high-temperature modification of NaNO2, which exists above 160°, has been observed. The fundamental frequencies for NO2— (in crystalline NaNO2) are: ν1(a1)=1328±2 cm−1 (N14),1303±2 (N15);ν2(a1)=828.2±0.4 (N14),823.6±0.4 (N15);ν3(b1)=1261±3 (N14). These are used to calculate the following force constants, in units of millidynes/A: fd=7.69±0.10,fα/d2=1.75±0.04,fdd=1.94±0.13,fdα/d=0.505±0.113.