SYNTHESIS, SPECTROSCOPIC, AND STRUCTURAL INVESTIGATION OF YTTERBIUM POTASSIUM HEXACYANOFERRATE-(II), YBKFE(CN)6 3.5H2O

Single crystals of the title compound are prepared by the U-tube slow diffusion method. The orthorhombic form of YbKFe(CN)6 · 3.5H2O crystallizes in space group Cmcm (No. 63, D172h with a = 7.186(3), b = 12.544(2), c = 13.433(3) Å, Z = 4, Dm = 2.6(1) Mg m-3, and Dx = 2.67 Mg m-3. The lattice constants were obtained from powder diffraction data, F(34) = 24(0.013, 106) and M20 = 22.0. The final least-squares full-matrix refinement based on 1316 unique reflections has yielded R = 0.041 and Rw = 0.046. Cyanide bridges link the nine-coordinated (TTP) YbN6(H2O)3 groups to the octahedral FeC6 groups. Cavities within the structure are occupied by uncoordinated zeolitic water molecules and potassium ions. Important mean bond lengths are: YbN = 2.337; YbO = 2.467; FeC = 1.891; and CN = 1.155 Å. © 1991.