The crystal structure of ammonium perchlorate-NH₄ClO₄

Abstract

The crystal structure of ammonium perchlorate has been redetermined. The orthorhombic cell with space-group Pnma has four molecules in a unit cell of dimensions a=9.13 Å, b=5.79 Å and c=7 .47Å. The values of the atomic co-ordinates have been refined by double Fourier-series methods and the final atomic positions determined are accurate to 0.02 Å. The positions of the hydrogen atoms have been obtained by the use of difference projection along the b-axis. In the structure each chlorine is surrounded tetrahedrally by four oxygen atoms at a mean distance of 1.46 Å. Each ammonium ion is surrounded by twelve oxygen atoms at distances varying from 2.89 to 3.39 Å. The four hydrogens surrounding each nitrogen form weak N-H ÅÅO bridges with the nearest oxygen atoms, Tables are given for various atomic co-ordinates and interatomic distances.