Hydrogen bonding in urea - art. no. 052101

The hydrogen bond consisting of a hydrogen atom positioned asymmetrically b etween a nitrogen and an oxygen atom (N-H . . .O) plays a central role in t he structure and functionality of proteins and amino acids. The urea crysta l is a simple system in which such a hydrogen bond exists. We have measured Compton profile anisotropies in crystalline urea which reveal subtle modul ations linked to this chen-deal bond. The data presented here have sufficie nt statistical accuracy to isolate features arising from intermolecular int eraction which is weak in urea and consequently difficult to detect experim entally.