The Molecular Structure and Hydrogen Bond Geometry in Liquid Formamide: Electron, Neutron, and X-Ray Diffraction Studies

Dedicated to Professor Alfred Klemm on the occasion of his 70th birthday Electron, neutron and X-ray diffraction patterns of l iquid fo rmamide have been measured at a temperature of 25 °C. Analysis of the diffraction data yields the molecular structure and the average geometry of the hydrogen bond. The molecular parameters obtained from liquid diffraction experiments are in good agreement with those f rom gas electron diffraction for the free molecule. The mean O . . . N and O . . . H hydrogen bond distances are 2.9 A and 1.9 A, respectively. Four H-bonds per molecule are found on the average. The deviation of the H-bonds from the linearity is estimated.