Stannous chloride, in solutions containing at least three mole equivalents of NaEC6H5, E = S and Se, forms triligated anions which crystallize readily as the tetraphenylarsonium salts, [(C6H5)4As[Sn(SC6H5)3], 1, and [(C6H5)4As][Sn(SeC6H5)3], 2. The crystals so formed are isomorphous, and their structures have been determined by single crystal X-ray diffractometry techniques. The salts crystallize in the monoclinic space group P21/c, with four formula units in unit cells of dimensions a = 10.760(1), b = 17.515(2), c = 20.247(3) Å, β = 104.71(1)° for 1, and a = 10.885(2), b = 17.587(2), c = 20.612(2) Å, β = 105.47(1)°, for 2. The structures have been refined by full-matrix least-squares techniques on F to agreement factors R = 0.024 (4780 observations with Fo > 3σ(Fo)) for 1, and R = 0.030 (3442 observations with Fo > 3σ(Fo)) for 2. The discrete [Sn(EC6H5)3]− anions are isostructural; the three S or Se atoms form the base of a triangular pyramid whose apex is occupied by the Sn atom. Two Sn—S distances in 1 are 2.532(1) and the third 2.552(1) Å, while in 2 the Sn—Se distances are 2.649(1), 2.650(1), and 2.671(1) Å. Angles at the Sn atom are 89.91(3), 90.55(3), and 96.73(3)° in 1, and 88.74(3), 89.72(3), and 97.27(3)° in 2. In both anions all three phenyl groups adopt a propeller-like conformation and are disposed in equatorial positions above the basal plane of chalcogen atoms. These salts represent the first thiolato- and sele-nolatostannates(II) to be characterized structurally. Tin-119 nmr spectra confirm that the [Sn(EC6H5)3]− ions are the same anionic Sn(II) species recently prepared insitu in solution.