Tris(Thiocyanato-Kappa N)Tris(Triphenylphosphine Oxide-Kappa O)Europium(Iii)-(Nitrato-Kappa O-2,O ')Bis(Thiocyanato-Kappa N)Tris(Triphenylphosphine Oxide-Kappa O)Europium(Iii) (1/1)

The title co-crystal, [Eu(NCS)(3)(C18H15OP)(3)][Eu(NCS)(2)(NO3)(C18H15OP)(3)], contains two distinct neutral complexes. Each complex has threefold symmetry about its central Eu3+ ion. As a result, the nitrate-containing molecule contains disorder of its bidentate nitrate and two N-bound thiocyanate anions, while the [Eu(NCS)(3)(OPPh3)(3)] complex is fully ordered. There is a weak pi-pi stacking interaction between the phenyl rings of the two molecules [centroid-centroid distance = 4.138 (4) angstrom].