YI 3 (Pr i OH) 4 (1), obtained from the reaction between yttrium chips and iodine in isopropanol, reacts with dioxygen to give a superoxide bridged dinuclear ionic species [Y 2 I 2 (μ 2 ,μ 0 :η 1 -O 2 ) 2 (Pr i OH) 8 ][I] 2 (2). The ligand exchange reaction of 1 with N,N-dimethylaminoethanol (dmaeH) afforded YI 3 (dmaeH) 4 (3). Complex 2 is the first structurally characterised yttrium superoxide derivative. In addition, it displays a rare μ 2 ,μ 0 :η 1 bonding mode of O2−, unknown in transition metal chemistry. 2 is also the first example of a superoxide derived from a metal iodide. The DFT calculations on a model compound, where the Pr i OH molecules of 2 are replaced by water molecules, i.e. for [Y 2 I 2 (μ 2 ,μ 0 :η 1 -O 2 ) 2 (H 2 O) 8 ][I] 2 (2a), show that this molecule is stable in its high spin triplet state with the SOMO–LUMO gap being 3.7eV.