Dark brown crystals were obtained from the system CoF2·4H2O – K2NbF7 – DH2 – Thio in aquamethanol solution, at slow evaporation at room temperature. In order to objectively determine the structure of this complex the X-ray study of the crystal was performed in monocrystalline phase. The crystal data: P21/n, a=145.139 Å, b=6.898 Å, c=21.484 Å, β=90.40°, Z=4, R=0.074. It was determined that compound comprises of complex cation [Co(DH)2(Thio)2]+, [NbF5(=O)]2- anion and a water molecule. In the case of the cation [Co(DH)2(Thio)2]+ the octahedral coordination of the metal atom takes place, which is common for trans-dioximates of Co(III). In each complex cation the two DH- residues coordinate through two N atoms, forming two coplanar metallocycles. The coordination polyhedron of the central atom to an octahedron is completed by two sulfur atoms of two thiocarbamide molecules, which are situated in trans position. The dimethylglyoxime residues in each cation are consolidated through intramollecular bonds O–H ···O, the distance O···O being 2.516 and 2.527 Å. The thiocarbamide molecules from the complex cation do not differ essentially from these determined for other bisdimethylglioximates of cobalt(III): one of the molecules is situated in such a way that it forms hydrogen bonds N-H···O with an oxygen atom of a DH- ligand, while the other is linked with the second DH- ligand from the equatorial plan of the complex through p···p interactions. The presence in complex cations of NH2 donor groups, in the [NbF5(=O)]2anion of five H-acceptor centres and of water molecules predetermines the formation of the specific coordination compound, as well as of the complex system of hydrogen bonds which links these components in the crystal. It should be mentioned that in the crystal the cations [Co(DH)2(Thio)2]+ form chains through hydrogen bonds O– H···O and N–H···S. Anions [NbF5(=O)]2- in the crystal are united in unidimensional chains through hydrogen bonds between anions and water molecules. These are united through direct hydrogen bonds N–H···F and N–H···O between cations and anions involving water molecules with the formation of the N–H···O(W)–H···F H-bonded fragments.figureStructure of the complex cation [Co(DH)2(Thio)2]+figureCrystal packing for [Co(DH)2(Thio)2]2[NbF5(=O)]·2H2O