Cs4[Sc6C]Cl13 und Cs4[Pr6(C2)]I13 — zwei Beispiele für das fehlende Bindeglied bei der Verknüpfung der Baueinheiten [M6Z]XX

Cs₄Sc₆C]Cl₁₃ and Cs₄Pr₆(C₂)]I₁₃ — Two Examples for the Missing Link in the Connectivity of M₆Z]X X Building Units Cs₄Sc₆C]Cl₁₃ (tetragonal, I4₁/amd, a = 1 540.5(4), c = 1 017.9(7) pm, c/a = 0.661, Z = 4, R = 0.038, R_w = 0.026) and Cs₄Pr₆(C₂)]I₁₃ (a = 1 804.9(3), c = 1 259.5(3) pm, c/a = 0.698, R = 0.106, R_w = 0.068) are obtained as green-black and blue-black single crystals with brass-like metallic lustre through metallothermic reduction of ScCl₃ and PrI₃, respectively, with cesium in the presence of carbon in sealed tantalum containers. The, overall, isotypic compounds contain isolated Sc₆C] and Pr₆(C₂)] clusters, respectively, that are surrounded by 18 halide (X) ligands (12 Xⁱ and 6 X^a; X = Cl or I). The connection is carried out via the motif M₆Z]XXXX (M = Sc and Pr; Z = C and C₂, respectively) and is thereby the missing link of the motifs of connection for the composition A_xM₆Z]X₁₃. Analogous interconnection of TiO₆] octahedra is found in the anatase-type of structure of TiO₂.