AbstractThe title tetranuclear complex, (m4-oxo)-hexakis(m2-chloro)-tetrakis(2-amino-1,3- thiazole-N)-tetra-copper(ii) [Cu4(m4-O)(m-Cl)6L4] (1, L = 2-amino-1,3-thiazole) was synthesized by the reaction of CuCl2×2H2O with 2-amino-1,3-thiazole in methanol and characterized by IR spectra and X-ray diffraction. Complex 1crystallizes in triclinic, space group Pwith a = 9.7137(2), b = 10.7005(2), c = 14.6505(2) Å,a= 83.9550(10), β = 82.0930(10), g = 67.1640(10)°,V = 1387.84(4) Å3, Mr = 883.43, Z = 2, m = 3.927 mm-1, Dc＝2.1144 g/cm3, F(000) = 868, R= 0.0332 and wR= 0.0814.The complex contains a tetrahedron of four CuII atoms coordinating to a central m4-O atom, with the six edges of the tetrahedron bridged by six Cl atoms. The Cu–O bond distances range from 1.910(2) to 1.918(2) Å, Cu–Cl from 2.3501(11) to 2.5924(10) Å, and Cu–Cu from 3.1003(6) to 3.1663(6) Å. The coordination geometries of the four coppers distort from trigonal bipramid to tetragonal pyramid with different distortion factors. The free animo groups of the ligands result in a lot of N–H···Cl and N–H···N intra- andintermolecular hydrogen bonds.