Crystal structure of bis-[cis-di-aqua-bis-(phen-an-thro-line)cobalt(II)] bis-(citrato)germanate(IV) dinitrate.

The asymmetric unit of the title compound, [Co(C12H8N2)2(H2O)2]2[Ge(C6H5O7)2](NO3)2, features two complex [(C12H8N2)2(H2O)2Co]2+ cations, two NO3 - anions as well as one centrosymmetric [(C6H5O7)2Ge]2- anion. Two HCit ligands (Cit = citrate, C6H4O7) each coordinate via three different oxygen atoms (hy-droxy-late, α-carboxyl-ate, β-carboxyl-ate) to the Ge atom, forming a slightly distorted octa-hedron. The coordination polyhedron of the Co atom is also octa-hedral, formed by coordination of four nitro-gen atoms from two phenanthroline mol-ecules and two water oxygen atoms. In the crystal, the cations and anions are linked by hydrogen bonds and form layers parallel to the bc plane. The structure exhibits disorder of the NO3 - anion [disorder ratio 0.688 (9) to 0.312 (9)]. There are also highly disordered solvent mol-ecules (presumably water and/or ethanol) in the crystal structure; explicit refinement of these mol-ecules was not possible, and the content of the voids was instead taken into account using reverse Fourier transform methods [SQUEEZE procedure in PLATON; Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unknown solvent mol-ecule(s).