Optical anisotropies of some organic molecules

The principal refractive indices of some organic crystals were obtained. The principal molecular refractivities of these crystals were determined using the equations for transitions from crystalline to molecular refractivities. The results show that strong optical anisotropy is always associated with strong magnetic anisotropy, in good agreement with that predicted by Krishnan, Guha & Banerjee [Philos. Trans. R. Soc. London Ser. A (1933), 231, 235-262]. The results also demonstrate the effect of substitution on the optical anisotropy in the case of aromatic compounds.