Crystal structure of anhydrous tripotassium citrate from laboratory X-ray powder diffraction data and DFT comparison

The crystal structure of anhydrous tripotassium citrate, [K 3 (C 6 H 5 O 7 )] n , has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The three unique potassium cations are 6-, 8-, and 6-coordinate (all irregular). The [KO n ] coordination polyhedra share edges and corners to form a three-dimensional framework, with channels running parallel to the c axis. The only hydrogen bond is an intramolecular one involving the hydroxy group and the central carboxylate group, with graph-set motif S (5).