Lithium dipotassium citrate monohydrate, LiK(2)C(6)H(5)O(7)(H(2)O)

The crystal structure of dilithium potassium citrate monohydrate, Li(+)·2K(+)·C(6)H(5)O(7) (3−)·H(2)O or LiK(2)C(6)H(5)O(7)·H(2)O, has been solved by direct methods and refined against laboratory X-ray powder diffraction data, and optimized using density functional techniques. The complete citrate trianion is generated by a crystallographic mirror plane, with two C and three O atoms lying on the reflecting plane, and chelates to three different K cations. The KO(8) and LiO(4) coordination polyhedra share edges and corners to form layers lying parallel to the ac plane. An intra­molecular O—H⋯O hydrogen bond occurs between the hydroxyl group and the central carboxyl­ate group of the citrate anion as well as a charge-assisted inter­molecular O—H⋯O link between the water mol­ecule and the terminal carboxyl­ate group. There is also a weak C—H⋯O hydrogen bond.