Dark red crystals of [K-(2,2,2)-crypt)] 2 Sn 5 precipitate after the reaction of (2,2,2)-crypt with a solution of K 1.33 Sn in liquid ammonia at room temperature. The compound is sensitive to oxidation and hydrolysis. The sequence of Raman bands (104, 120, 133 and 180 cm ±1 ) is characteristic for the trigonal bipyramidal closo-[Sn 5 ] 2± cluster anion. The wave numbers correspond with the data from Hartree-Fock calculations (114, 128, 142 and 187 cm ±1 ). The compound crystallizes trigonally (a = 11.736 A Ê , c = 22.117 A Ê , Z = 2, space group P3c1 (No. 165); Pearson code hP262), isotypic with [Na-(2,2,2)-crypt)] 2 Pb 5 . The atoms of the cluster show strange anisotropic displacements, which are perfectly reducible to a helical rigid-body motion around and along [001] (libration: ± 9.5°; translation ± 0.29 A Ê ). The structure can be described as a hierarchical derivative of the initiator CaIn 2 (P6 3 /mmc, hP6), generated by an atom-to-aggregate replacement: [Ca][In] 2 = [Sn 5 ][K @ C 36 H 72 N 4 O 12 ] 2 . Thus, the distribution of the [Sn 5 ] 2± Zintl anions is hexagonal primitive, and the cation complexes are located close to the centers of trigonal superprisms formed by Sn 5 clusters.