An aquazinc(II) complex of 1,10-phenanthroline with fumarate counter-ions

In the title compound, diaquabis(1,10-phenanthroline- kappa(2) N,N') zinc(II) fumarate tetrahydrate, [Zn(phen)(2)(H2O)(2)] L.-4H(2)O, where phen is 1,10-phenanthroline (C12H8N2) and L2- = fumarate (C4H2O4), the zinc(II) cation is six-coordinated by two water molecules and four N atoms from two phen molecules. Each of the two independent L2- anions is located about an inversion centre and does not coordinate to zinc( II) cations, acting rather as a counter-ion. The water molecules and L2- anions are linked through a complicated hydrogen-bonding network to form a three-dimensional structure.