Experimental and theoretical vibrational study of methylene bis(thiocyanate), CH2(SCN)2. A comparison with thiocyanogen, (SCN)2

•The infrared and Raman spectra of CH2(SCN)2 are obtained.•Bands in the spectra of the CH2(SCN)2 and (SCN)2 molecules are assigned after comparison with the calculated frequencies.•The experimental frequencies of both molecules are reproduced with calculated Scaled Quantum Mechanics force fields.•A comparison of the internal force constants shows similar values for the equivalent bonds in both molecules.

The infrared and Raman spectra of methylene bis(thiocyanate), CH2(SCN)2, were obtained. The observed bands were assigned to the different normal modes of vibration using the results of a DFT calculation of the molecular vibrational properties. These results and the experimental data were used to define a Scaled Quantum Mechanics force field for the molecule. A similar treatment was applied to the thiocyanogen molecule, (SCN)2, for which the experimental frequencies were already reported in the literature. The sets of internal force constants for both molecules show very similar values.

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