Two triorganotin(IV) phosphonate compounds were isolated and structurally investigated by infrared and Mössbauer spectroscopies and X-ray crystallography. The reactionoftrimethyltin(IV) chloride (SnMe3Cl) and hexamethylenetetraammonium hydrogen methylphosphonate[CH3PO3H][N4(CH2)6H] led to the formation of [C10H34O4P2Sn3] (1) which crystallizes in the Monoclinic space group Pn with Z = 2, a = 8.4955 (2) ?, b = 11.318 (3) ?, c = 11.902 (2) ?, β = 90.9340 (10)? and V = 1144.2 (4) ?3. An uncommon decomposition of methylphosphonate occurred during the reaction process giving rise to the formation of dimers of [SnMe3PH2SnMe3]+. The structure of 1 consists of an anionic chain of [CH3PO3(SnMe3PH2SnMe3)]? linked to [SnMe3(H2O)]+ moieties through Sn?O bonds involving the remaining oxygen atoms of the methylphosphonates. In the chain, each SnMe3 residue is coordinated by one methylphosphonate and one phosphor atom, in a trans-trigonal bipyramidal PSnC3O geometry. The environment at tin atoms in both SnMe3 moieties is an octahedron. The methylphosphonate anion is otherwise in a general position and behaves as a tri-coordinating ligand. The reactionoftriphenyltin(IV) hydroxide (SnPh3OH) and phosphorous acid (HPO(OH)2) led to the formation of [C36H31O3PSn2] (2) which crystallizes in the Monoclinic space group P2/n with Z = 4, a = 11.7966 (4) ?, b = 10.1953 (4) ?, c = 27.6715 (10) ?, β = 94.600 (2)? and V = 3317.3 (2) ?3. The structure of 2 is comprised of an anionic chain of [HPO3(SnPh3)]? linked to SnPh3 moieties through Sn?O bonds involving the remaining oxygen atoms of the hydrogenphosphonates. In the chain the SnPh3 residues are each one coordinated by two hydrogenphosphonates in a trans-trigonal bipyramidal OSnC3O arrangement. The geometry at tin atoms within the monocoordinated SnPh3 moieties connected to the chain is a distorted tetrahedron. The hydrogenphosphonate anion is in a general arrangement and behaves as a tri-O-coordinating ligand.Read less <