The crystal structure of ammonium oxide

Abstract

At low temperatures ammonia forms two stable hydrates NHs.H~O and 2NHs.H~O , ammonium hydroxide and ammonium oxide respectively. The hydroxide is hexagonal with a = 11-21=1=0.05/~ and c = 4.53±0.02/~ at --95:t= 10 ° C. The oxide is orthorhombic (space group Pbnm) with a = b = 8.41±0.03 /~ and c = 5-33±0.02 /~ at --95±10 ° C. The structure of ammonium oxide contains planar chains of alternating ammonia and water molecules bonded by hydrogen bonds of the OH... N and N-H. • • O type. The chains are cross linked into a three-dimensional lattice by hydro-gen bonds of the latter type. The open spaces in the lattice contain the remaining ammonia mole-cules, each having a single hydrogen bond to the molecular lattice.