On allowing PhPO3H2 to react with SnPh3Cl in ethanolic media, OC[OPOSnPh3OEt]2 is obtained by cetonization, desarylation and esterification, has been studied by infrared technic. A discrete structure has been suggested on the basis of infrared data, the anion behaving as a bidentate ligand, the environment around the tin centres being tertrahedral.