The cerium ion in the title compound, [Ce(OH2)(6)](2) [Cu(OH2)(4)](C4O4)(4)
. 2H(2)O, is nine-coordinate in a monocapped square-prismatic geometry. Th
e squarate (3,4-dihydroxy-3-cyclobutene-1,2-dionate) group links the cerium
and copper ions into a three-dimensional network structure.