By reaction of SnI2, SnI4, and crown ether (18-crown-6) in the ionic liquid [NMe(n-BU)(3)][N(Tf)(2)], Sn3I2(18-crown-6) is obtained in the form of black, plate-shaped crystals and crystallizes with a monoclinic lattice symmetry. In detail, Sn3I8 center dot 2(18-crown-6) is constituted of trigonal-bipyramidal [SnI5](-)-anions and [Sn2I3(18-crown-6)(2)](+)-cations. The cation exhibits an endocyclical coordination of Sn2+ by the crown ether. Both constituents are linked via long-ranging 1-1 contacts to form an infinite network. Besides crystal structure analysis, the mixed valence state of tin is evidenced by Sn-119-Mossbauer spectroscopy.