Di--butyl-tin(IV)-hydroxide-iodide, BuSn(OH)I, the last missing member in the series of pure di--butyl-tin(IV)-hydroxide-halides.

The crystal structure of di--butyl-hydroxido-iodido-tin(IV), [Sn(CH)I(OH)] or BuSn(OH)I, consists of dimeric, centrosymmetric mol-ecules exhibiting the typical structural features of diorganotin(IV)-hydroxide-halides, Sn(OH). Two trigonal-bipyramidally coordinated tin(IV) atoms are bridged two hydroxyl groups, resulting in a planar, four-membered {Sn-O} ring of rhombic shape, with acute angles at tin, obtuse angles at oxygen and two different Sn-O distances depending whether the oxygen atom adopts an axial or equatorial position at the tin(IV) atom. In contrast to its fluorine, chlorine and bromine homologues, no hydrogen bonds between the OH group and the halide atom exist, confining the inter-molecular inter-actions to van der Waals forces.