Conformation Isomerism of Nonagermanide Ions. Crystal Structures of Brown and Red [K-([2.2.2]crypt)]6Ge9Ge9·(ethylenediamine)x (x = 0.5, 1.5)

A brown and a red form of the [K-([2.2.2]-crypt)]+ salts of naked polyhedral nonagermanide anions were isolated by dissolving the alloy K4Ge9 in ethylenediamine. The compounds [K-([2.2.2]crypt)]6Ge9Ge9·(ethylenediamine)x with x = 0.5 (2a, brown) and 1.5 (2b, red) crystallize in the P1 space group with two independent cluster anions and six [K-([2.2.2]-crypt)]+ units. The structures are almost isotypic, but differ by their cell parameters at 233 K (2a, a = 14.397(1) A, b = 19.765(2) A, c = 28.898(2) A, α = 87.485(9)°, β = 79.168(9)°, γ = 85.415(8)°; 2a, a = 14.503(1) A, b = 19.924(2) A, c = 28.935(3) A, α = 87.43(1)°, β = 80.85(1)°, γ = 85.92(1)°) and atomic parameters. The differences arise with two additional ethylenediamine molecules in the case of red 2b. These solvent molecules were refined at 50% occupancy. The solvent molecules have a significant influence on the color of the crystals and the conformation of the deltahedral anions. The structures of the clusters correspond to C2v distorted polyhedr...