Dear Netters, Does anyone know how to calculate refractive index of a molecule? I know it can be estimated using molar refractivities for each bond , but I can't find a table of these that includes a C=N bond. Is there a better way to calculate this property, maybe using computationally obtained values for polarizability? Thanks in advance, Brad Kaufman Bryn Mawr College bkaufman : at : cc.brynmawr.edu