Hexa-mu-chloro-mu4-oxo-tetrakis[[5-(2,4,6-trimethylphenyl)pyrazole-kappaN2]copper(II)].

The title compound, [Cu(4)Cl(6)O(C(12)H(14)N(2))(4)], is a new example of the well known [Cu(4)(mu(4)-O)(mu-X)(6)L(4)] class of complex (X(-) is Cl(-), Br(-) or I(-), and L is a monodentate ligand). The molecule has crystallographic C(2) symmetry, with two Cl(-) ions on each edge of a Cu(4) tetrahedron. Two of these, on opposite edges of the tetrahedron, accept intramolecular hydrogen bonds from two of the pyrazole N-H donors.