Single-crystal structure and electron density distribution of ammonia at 160 K on the basis of X-ray diffraction data

A single-crystal of ammonia, NH3, was grown in a thin-walled capillary at 178 K, and high-resolution X-ray diffraction data were obtained for this compound at 160 K in order to obtain information about electron density distribution. Conventional and multipole refinements and deformation electron density maps indicated small but significant N-H bond bending inside the NH3 tetrahedron that is in agreement with ab initio quantum-chemical calculations and the VSEPR model, Topological analysis of the experimental charge density distribution in the ammonia molecule has been performed, and the data are compared with high-level quantum-chemical calculations, Some features of the intermolecular hydrogen bonds in the crystal are discussed.