The crystal structure of poly[μ-citrato-dilithium(I)potassium(I)], [Li2K(C6H5O7)] , 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 carboxyl-ate, and the terminal carboxyl-ate. The KO7 coordination polyhedra share edges, forming chains parallel to the a axis. These chains share edges with one tetra-hedral Li ion, and are bridged by edge-sharing pairs of the second tetra-hedral Li ion, forming layers parallel to the ac plane.