The rhenium diisocyanide complex fac-[Re(O)Cl-3(CNC6H3-(CH3)(2)-2,6)(2)] (1) was obtained by reaction of mer-[Re(O)Cl-3(SMe2)-(OPPh3)] with 2 equiv. of the ligand 2,6-dimethylphenylisocyanide. In the presence of water complex 1 reacts under HCl evolution to yield [(2,6-(CH3)(2)-C6H3NC)(2)Cl-2(O)Re-O-Re(O)Cl-2(CNC6H3-(CH3)(2)-2,6)(2)] (2) The dinuclear complex 2 was shown by X-ray crystallography to contain an almost linear O=Re-O-Re=O core. Crystals of 2, C36H36Cl4N4O3Re2, are orthorhombic, space group Pccn (No. 56) with a = 11.169(9), b = 13.761(4), c = 25.831(6) Angstrom, Z = 4 and D-c = 1.818 g cm(-3). (C) 1998 Elsevier Science S.A.