FTIR spectra of cyanamide complexes with hydrogen fluoride in solid argon

Cyanamide vapor was condensed at 12 K with HF in excess argon producing a 1:1 complex of the form H₂NCN-HF. The HF submolecule stretching fundamental was observed at 3458 cm^-1, and the HF librational modes appeared at 694 and 686 cm^-1, which are very similar to the HF modes observed for the CH₃CN-HF complex. Several perturbed submolecule modes of cyanamide in the 1:1 complex were identified; large perturbations for the C≡N stretch at 2306 cm^-1 and the N-C stretch at 1113 cm^-1 and a small blue shift for the NH₂ wag at 427 cm^-1 support bonding of HF to the nitrile nitrogen. Increasing the HF concentration favored a 1:2 complex H₂NCN-(HF)₂ with two HF stretching modes appropriate for an open-chain structure.