Geometrical Constitution of Silicichloroform

POLARIZATION measurements of Raman lines of chloroform made by Cabannes1 and discussed by him show that this molecule has not a perfect pyramidal symmetry. On the other hand, recent electron diffraction measurements discussed by Degard2 are not able to fix with precision the position of the carbon atom in the chloroform molecule. Is it so, also, for silicichloroform? To measure the state of polarization of the Raman lines of silicichloroform we employed the same method as that used by Cabannes. Optical parts of the instrument were made by the Société Belge d'Optique; we have to thank M. Cailler, director of that company, for his kindness. The spectrograph used was a Hilger E 443. The following results were obtained: