catena-Poly[[μ(3)-hydroxido-tetra-μ(2)-pyrid-azine-1:2κN:N';1:3κN:N';2:3κN:N'-tetrakis(selenocyanato)-1κN,2κN,3κN-trizinc(II)]-μ-cyanido-1:2'κC:N].

In the crystal structure of the title compound, [Zn(3)(NCSe)(4)(OH)(CN)(C(4)H(4)N(2))(4)](n) one of the two crystallograph-ically independent zinc(II) cations is coordinated by two terminal N-bonded seleno-cyanato anions and two N atoms of two symmetry-related pyridazine ligands in a trigonal-bipyramidal geometry, while the other zinc(II) cation is coordinated by one terminal N-bonded seleno-cyanato anion, one μ-1,2-cyanido anion and three N atoms of three crystallographically independent pyridazine ligands in a slightly distorted octa-hedral coordination geometry. The zinc(II) atoms are further connected via a μ(3)-hydroxido anion into trinuclear building blocks. The formula unit consists of three zinc cations, four seleno-cyanato anions, one μ(3)-hydroxido anion, four pyridazine mol-ecules as well as one cyanido anion. The asymmetric unit contains half of a formula unit. One of the zinc atoms, two seleno-cyanato anions, two pyridazine ligands and the μ(3)-hydroxido anion are located on a crystallographic mirror plane, whereas the cyanido anion is located on a twofold rotation axis. Therefore, this anion is disordered due to symmetry. The cyanido anions connect the metal centres into polymeric zigzag chains propagating along the a axis.