The complex formation of uranyl UO22+ with chloride ions in acetonitrile was studied by UV-vis and U L-III EXAFS spectroscopy. The investigations unambiguously point to the existence of a [UO2Cl4](2-) species in solution with D-4h symmetry. The distances in the U(VI) coordination sphere are U-O-ax = 1.77 +/- 0.01 angstrom and U-Cl = 2.68 +/- 0.01 angstrom.