Trisodium citrate, Na(3)(C(6)H(5)O(7))

The crystal structure of anhydrous tris­odium citrate, Na(3)(C(6)H(5)O(7)), has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory (DFT). There are two independent five-coordinate Na(+) and one six-coordinate Na(+) cations in the asymmetric unit. The [NaO(5)] and [NaO(6)] polyhedra share edges and corners to form a three-dimensional framework. There are channels parallel to the a and b axes in which the remainder of the citrate anions reside. The only hydrogen bonds are an intra­molecular one between the hy­droxy group and one of the terminal carboxyl­ate O atoms and an intermolecular one between a methylene group and the hydroxyl O atom.