Octamethyl-1κ2 C,2κ2 C,3κ2 C,4κ2 C-bis(μ2-2-methylpyrazine-5-carboxylato)-1:2κ2 O: O;3:4κ2 O: O-bis(2-methylpyrazine-5-carboxylato)-1κ O,4κ O-di-μ3-oxido-1:2:3κ3 O: O: O;2:3:4κ3 O: O: O-tetratin(IV) hexahydrate

The title compound, [Sn4(CH3)8(C6H5N2O2)4O2]·6H2O, is a hydrated cluster containing four Sn atoms, built up by inversion symmetry around the central Sn2O2 ring. The Sn-atom coordination geometry might be regarded as very distorted SnO3C2 trigonal–bipyramidal or possibly as grossly distorted SnO3C2N octahedral. All the cluster non-H atoms, with the exception of the Sn-bonded methyl groups, lie on a mirror plane. Two of the water-molecule O atoms have m site symmetry; the other occupies a twofold rotation axis. [ABSTRACT FROM AUTHOR]