Crystal structure of bis­­(benzoato-κO)di­butyl­tin(IV), nBu2Sn(bzo)2

The title compound, [Sn(C4H9)2(C6H5COO)2], was synthesized in order to study the inter­action between di-n-butyl­tin(IV) oxide and some carb­oxy­lic acids. Di-n-butyl­tin(IV) dibenzoate, nBu2Sn(obz)2, exhibits the same structural features as other diorganotin(IV) dibenzoates characterized by an unsymmetrical bidentate bonding mode [Δ(Sn—O) ≃ 0.4 Å] of the two benzoate groups to tin. In a first approximation, the coordination sphere at tin resulting from the two stronger bonded O atoms [2.1227 (17) and 2.1405 (16) Å] and the two α-C atoms of the n-butyl groups [2.125 (3) and 2.129 (2) Å] is compressed to a tetra­gonal disphenoid [〈(C—Sn—C) = 148.2 (1)° and 〈(O—Sn—O) = 82.01 (6)°]. This coordination sphere is expanded by the less strongly bonded two O atoms [2.507 (2) and 2.485 (2) Å] to a substanti­ally distorted octa­hedron and by a weak inter­molecular Sn⋯O inter­action [2.943 (2) Å] to a penta­gonal bipyramid with the formation of centrosymmetric dimers. The unbranched butyl groups adopt two different conformations: anti–gauche [torsion angles: 166.0 (2)–63.9 (4)°] and gauche–gauche [65.0 (3)–56.3 (3)°]. Inter­molecular inter­actions between the dimers are restricted to O⋯H—C contacts (2.64 Å) and van der Waals inter­actions.