catena-Poly[[[aqua(7-hydroxy-2H-1-benzopyran-2-one)sodium]-di-μ-aqua] 2-oxo-2H-1-benzopyran-7-olate monohydrate].

The asymmetric unit of the title compound, {Na(C(9)H(6)O(3))(H(2)O)(3)·H(2)O}(n), contains two crystallographically independent Na atoms, two 7-hy-droxy-coumarin ligands, six coordinated water mol-ecules, two 7-hy-droxy-coumarin anions and two uncoordinated water mol-ecules. Both Na atoms exhibit a distorted octa-hedral coordination geometry and are coordinated by five water O atoms and the terminal O atom from a 7-hy-droxy-coumarin ligand. Four of the water mol-ecules are bridging, whereas the fifth is terminal. Na-O bond distances are in the range 2.288 (2)-2.539 (2) Å. In the chains, extending parallel to [100], adjacent Na atoms are separated by 3.60613 (7) Å. The uncoordinated water mol-ecules and 7-hy-droxy-coumarin phenolate anions are located between the chains and are hydrogen bonded to the chains.