New one-dimensional uranyl and neptunyl iodates: crystal structures of K-3[(UO2)(2)(IO3)(6)](IO3)center dot H2O and K[NpO2(IO3)(3)]center dot 1.5H(2)O

摘要

The uranyl and neptunyl(VI) iodates, K-3[(UO2)(2)(IO3)(6)](IO3) . H2O (1) and K[NpO2(IO3)(3)] . 1.5H(2)O (2), have been prepared and crystallized under mild hydrothermal conditions. The Structures of I and 2 both contain one-dimensional (1)(x) [AnO(2)(IO3)(3)](1-)(An = U, Np) ribbons that consist of approximately linear actinyl(VI) cations bound by iodate anions to yield AnO(7) pentagonal bipyramids. The AnO(7) units are linked by bridging iodate anions to yield chains that are in turn Coupled by additional iodate anions to yield ribbons. The edges of the ribbons are terminated by monodentate iodate anions. For 1 and 2. K+ cations and water molecules separate the ribbons from one another. In addition, isolated iodate anions are also found between (1)(x) [UO2(IO3)(3)](1-) ribbons in 1. In order to aid in the assignment of oxidation states in neptunyl containing compounds, a bond-valence sum paraineter of 2.018 Angstrom for Np(VI) bound exclusively to oxygen has been developed with b = 0.37Angstrom. Crystallographic data (193K, MoKalpha, lambda = 0.71073): 1, triclinic, P (1) over bar, a = 7.0609(4) Angstrom, b = 14.5686(8) Angstrom, c = 14.7047(8) Angstrom, 119.547(1)degrees, beta = 95.256(1)degrees, gamma = 93.206(1)degrees, Z=2, R(F) = 2.49% for 353 pparameters with 6414 reflections with I>2alpha(I); (203K, MoKalpha, lambda = 0.71073): 2, monoclinic, P2(1)/c, a = 7.796(4) Angstrom, b = 7.151(3) Angstrom, c = 21.79(1) Angstrom, beta = 97.399(7)degrees, Z=4, R(F)=6.33% for 183 parameters with 2451 reflections with I > 2alpha(I). (C) 2003 Elsevier Inc. All rights reserved. [References: 35]