抄録
The method of minimum deviation was employed to measure the temperature dependence and the dispersion of principal indices of refraction of NaNO2 crystal. Their room temperature values have been found to be na=1.3455, nb=1.4125 and nc=1.6547. The temperature dependence of the birefringence were measured by a Berek compensator. Slight anomalies were found at the transition point. The anisotropic electronic polarizability of a nitrite ion was calculated from the experimental data of refractive indices based on the point-dipole approximation and has been found to be 2.240, 2.716 and 4.610Å3 along the a, b and c axis, respectively, at room temperature. It was concluded that the large optical anisotropy in this substance mainly arises from the polarizability anisotropy of the nitrite ion.
