Infrared spectrum of formamide in the solid phase

Infrared spectra of solid formamide are reported as a function of temperature. Solid formamide samples were prepared at 30 K and then annealed to higher temperatures (300 K) with infrared transmission spectra being recorded over the entire temperature range. The NH2 vibrations of the formamide molecule were found to be particularly very sensitive to temperature change. The IR spectra revealed a phase change occurring in solid formamide between 155 and 165 K. Spectral changes observed above and below the phase transition may be attributed to a rearrangement between formamide dimers and the formation of polymers is proposed at higher temperatures.

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► IR spectra recorded at multiple temperatures show conformers of formamide dimers.
► Formamide amorphous and crystalline ice spectra were found to be much different.
► The NH2 vibrations in formamide molecule were very sensitive to temperature changes.
► Morphological changes as well as rearrangement between dimers in solid formamide.