Crystal structure of anhydrous potassium carbonate

Abstract

Crystals of the title compound are monoclinic, space group P2₁/c with unit cell dimensions: a= 5·64, b= 9·80, c= 6·88 Å, β= 98·8°. The structure, which was determined from photographic X-ray data by Patterson and Fourier methods, consists of a slightly distorted hexagonal close packed array of carbonate ions in which potassium ions occupy both octahedral and trigonal bipyramidal sites. The carbonate ions have non-crystallographic trigonal planar geometry to within the accuracy of this determination. The structure was refined by least-squares methods to R 0·129 for 316 observed reflections.