The Intensities of Several of the Infra-Red Absorption Bands of Cyanogen and Cyanogen Chloride

Measurement of the absolute intensities of several infra‐red absorption bands of cyanogen and cyanogen chloride gives the following values in cycles per cm at N.T.P. $$\begin{array}{ccc}\mathrm{Cyanogen}& \mathrm{Band}& \mathrm{Intensity}\\ & \text{2150\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}& {\text{90×10}}^{10}\\ & & \\ \mathrm{Cyanogen\; chloride}& \mathrm{Band}& \mathrm{Intensity}\\ & \text{714\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}& {\text{17×10}}^{10}\\ & \text{2214\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}& {\text{220×10}}^{10}\end{array}$$ Values of the variation in bond moments with change in bond length are calculated on the basis of bond moment additivity. This leads to widely different values of this derivative for the CN bond in the two molecules. The infra‐red spectrum of cyanogen chloride from 2 to 20 microns is reported.