Molecular Structure of Acetamide as Studied by Gas Electron Diffraction

The bond distances (rg) and angles (rα) in acetamide CH3CONH2 have been determined by gas electron diffraction as follows: C–C=1.519±0.006 Å, C–N=1.380±0.004 Å, C=O=1.220±0.003 Å, C–H (average)=1.124±0.010 Å, N–H (average)=1.022±0.011 Å, ∠N–C=O=122.0±0.6°, ∠C–C–H (average)=109.8±2°, and ∠C–C–N=115.1±1.6° (or 112.2±1.6°). In comparison with the molecular structure in the crystal, the C–N bond is about 0.05 Å longer, whereas the C=O bond is about 0.04 Å shorter. The C–N and C=O bonds appear to be slightly shorter than the corresponding bonds in N-methylacetamide.