Das erste oligomere Oxoferrat(III): K14[Fe4O13]

The First Tetraferrate(III): K₁₄Fe₄O₁₃] For the first time K₁₄Fe₄O₁₃] was obtained by annealing intimate mixtures of K₂O and LiFeO₂ (molar ratio 2.2:1) in closed Ni-cylinders (6 months, 610°C) in the form of yellow-brown single crystals. The structure determination (four circle diffractometer, MoKα, 3377 of 3377 I_o(hkl); R = 4,52%, R_w = 2,53%) confirms the space group P2₁/c; a = 677.9, b = 2956.2, c = 672,1 pm, β = 120.31°, Z = 2. Essential part of the structure are tetranuclear Fe₄O₁₃]^14?-groups, oligomers consisting of four corner-sharing FeO₄-tetrahedra. Within the structure these groups are connected by two crystallographically distinct K-particles thus forming bands which are arranged according to a ?closest packing of bands”? interconnected by the rest of the K-particles. The structure is described via Schlegel-diagrams. It is isotypic with Na₁₄Al₄O₁₃].