Structure of a citrate double salt: potassium dihydrogen citrate-lithium potassium hydrogen citrate monohydrate

The crystal structure of a double salt of potassium dihydrogen citrate and lithium potassium hydrogen citrate monohydrate has been determined. One potassium ion is coordinated with eight O atoms and the other with nine O atoms at M--O distances in the range 2.660 (1) to 3.139 (1) A. Two of these O atoms are shared by both potassium ions. The lithium ion is tetrahedrally surrounded by four O atoms at distances in the range 1.870 (3) to 1.988 (3) A. This crystal structure contains nine hydrogen bonds in the asymmetric unit. The water molecule connects different citrate ions along the c direction by hydrogen bonding.