Poly[di-μ₉-citrato-tetra­sodiumzinc]

In the title compound, [Na₄Zn(C₆H₅O₇)₂]_n, the Zn^II ion lies on an inversion center and is coordinated by six O atoms from two citrate ligands, forming a distorted octa­hedral geometry. There are two crystallographically independent Na⁺ cations in the asymmetric unit. One Na⁺ cation exhibits a distorted square-pyramidal geometry defined by five O atoms from four citrate ligands. The other Na⁺ cation is surrounded by six O atoms from five citrate ligands in a distorted octa­hedral geometry. The Na⁺ cations are bridged by citrate carboxyl­ate groups, forming a layer parallel to (100). The layers are further assembled into a three-dimensional network with the [Zn(citrate)₂]⁴⁻ building units as `pillars'; O—H...O hydrogen bonds also stabilize the structure.