Crystal structure of dilithium potassium citrate, Li(2)KC(6)H(5)O(7) determined from powder diffraction data and DFT calculations

The crystal structure of poly[μ-citrato-dilithium(I)potassium(I)], [Li(2)K(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 citrate anion triply chelates to the K(+) cation through the hydroxyl group, the central carboxyl­ate, and the terminal carboxyl­ate. The KO(7) coordination polyhedra share edges, forming chains parallel to the a axis. These chains share edges with one tetra­hedral Li ion, and are bridged by edge-sharing pairs of the second tetra­hedral Li ion, forming layers parallel to the ac plane.