Crystal structure of tetrakis(μ-n-butyrato-κ² O:O')bis[chloridorhenium(III)](Re-Re)

With an inversion center at the mid-point of the two Re^III atoms, the title compound, [Re2Cl2{O2C(CH2)2CH3}4], exhibits a paddle-wheel or lantern-type structure with four n-butyrate groups bridging two Re^III atoms in a syn-syn fashion. The axial chloride ligands together with the Re-Re quadruple bond [2.2330(3)Å] complete an essentially octahedral geometry around each Re^III atom. There is little distortion, with an Re-Re-Cl bond angle of 176.18(3)° and typical cis-O-Re-O bond angles ranging from 89.39(11) to 90.68(11)°. There are two molecules in the unit cell, and no significant intermolecular interactions were noticed between molecules in the crystal.