Syntheses, structures, and vibrational spectroscopy of the two-dimensional iodates Ln(IO3)3 and Ln(IO3)3(H2O) (Ln=Yb, Lu)

The reaction of Lu3+ or Yb3+ and (HIO6)-I-5 in aqueous media at 180 degrees C leads to the formation of Yb(IO3)(3)(H2O) or LU(IO3)(3)(H2O), respectively, while the reaction of Yb metal with H5IO6 under similar reaction conditions gives rise to the anhydrous iodate, Yb(IO3)(3). Under supercritical conditions Lu3+ reacts with HIO3 and KIO4 to yield the isostructural Lu(IO3)(3). The structures have been determined by single-crystal X-ray diffraction. Crystallographic data are (MoK alpha, lambda = 0.71073 angstrom): Yb(IO3)(3), monoclinic, space group P2(1)/n, a = 8.6664(9) angstrom, b = 5.9904(6) angstrom, c = 14.8826(15) angstrom, beta = 96.931(2)degrees, V = 766.99(13), Z = 4, R(F) = 4.23% for 114 parameters with 1880 reflections with I > 2 sigma(I); LU(IO3)(3), monoclinic, space group P2(1)/n, a = 8.6410(9), b = 5.9961(6), c = 14.8782(16) angstrom, beta = 97.028(2)degrees, V = 765.08(14), Z = 4, R(F) = 2.65% for 119 parameters with 1756 reflections with I > 2 sigma(I); Yb(IO3)(3)(H2O), monoclinic, space group C2/c, a = 27.2476(15): b = 5.6296(3), c = 12.0157(7) angstrom, beta = 98.636(1)degrees, V = 1822.2(2), Z = 8, R(F) = 1.51% for 128 parameters with 2250 reflections with I > 2 sigma(I); LU(IO3)(3)(H2O), monoclinic, space group C2/c, a = 27.258(4), b = 5.6251(7), c = 12.0006(16) angstrom, beta = 98.704(2)degrees, V = 1818.8(4) Z = 8, R(F) = 1.98% for 128 parameters with 2242 reflections with I > 2 sigma(I). The f elements in all of the compounds are found in seven-coordinate environments and bridged with monodentate, bidentate, or tridentate iodate anions. Both Lu(IO3)(3)(H2O) and Yb(IO3)(3)(H2O) display distinctively different vibrational profiles from their respective anhydrous analogs. Hence, the Raman profile can be used as a complementary diagnostic tool to discern the different structural motifs of the compounds. (c) 2006 Elsevier Inc. All rights reserved.