Bernd Ziegler

Die Kristallstruktur des Cyanospinells K2Cd(CN)4

The crystal structure of cubic K2Cd(CN)4 (a = 1286.01(9) pm, Fd 3̅ m, Z = 8) was determined from 175 independent X-ray single crystal reflections (w R = 0.0178). Regular [Cd(CN)4]2- tetrahedra (Cd - C = 222.5(3), C - N = 111.3(3) pm) and strongly trigonally elongated [KN6] octahedra ( K - N = 293.0(2) pm) are arranged in a normal spinel type manner.

Röntgenstrukturuntersuchungen an Elpasolith-verwandten Hexacyanokomplexen [N(CH3)4]2A[M(CN)6] (A = Rb, Tl; M = Cr, Fe) / X-Ray Structure Investigations of Elpasolite Related Hexacyano Complexes [N(CH3)4]2A[M(CN)6] (A = Rb, Tl; M = Cr, Fe)

Abstract Single crystals were prepared and X -ray structure determinations performed of the hexagonal com pounds (R3̄m, Z = 3) [N(CH3)4]2RbCr(CN)6 (a = 895.9, c = 2176.4 pm), [N (CH3)4],TlCr(CN)6 (a = 894.0, c = 2168.4 pm), [N(CH3)4],RbFe(CN)6 (a = 886.7, c = 2149.9 pm ) and of monoclinic [N(CH3)4]2TlFe(CN)6 (C2/c, Z = 4; a = 1511.4, b = 884.8, c = 1525.9 pm , β = 110.0°). The structure of the hexagonal complexes is closely related to that of cubic elpasolites, showing, however, orientational disorder of the tetramethylammonium groups. Within the monoclinic TIFe-compound this group has fixed orientation, which makes some of the Fe-CN-Tl bridges bent, contrary to the linear M-CN -A array within the hexagonal compounds. Details and relations are discussed with respect to similar hexacyano complexes.

Hydratisierte Cyanoelpasolithe: Bis(tetramethylammonium)diaquaIithium-hexacyanometallate(III) des Mangans, Eisens und Cobalts / Hydrated Cyanoelpasolites: Bis(tetramethylammonium)diaqualithium-hexacyanometallates(III) of Manganese, Iron and Cobalt

The crystal structures of three isotypic hexacyanometallates(III) (NMe4)2LiM(CN)6·2H2O have been determined and refined in the monoclinic space group C2/c, Z = 4, to wR = 0.053 (M = Mn, 959 independent single crystal reflections), 0.041 (M =Fe, 2002 reflections) and 0.037 (M = Co, 1881 reflections). The stucture is elpasolite-related by its face-centered pseudocubic arrangement of M atoms within nearly undistorted M(CN)63- octahedra, six of which form strongly distorted octahedral N6 cavities occupied by dihydrated lithium ions. The resulting average distances for the M(CN)63- octahedra are Mn-C = 201, Fe-C = 194.7, Co-C = 190.3, and C-N = 114 pm. The lithium coordination is distorted tetrahedral, consisting of LiO2N2 units with distances of about Li-O = 194, Li -N = 209 pm (for M = Fe, Co). The remaining four N atoms of the N6 cavity are bound by hydrogen bridges from the two aqua ligands, O-H···N = 283 and 295 pm. The relations to the hydrated elpasolite structure of (NMe4)2NaFe(CN)6·H2O are discussed.