Intercalation of KCl into layered neptunyl and plutonyl iodates

The hydrothermal reaction of Np(IV) or Pu(IV) with KIO4 and CsCl at 180degreesC for 1 day results in the formation of NpO2(IO3)(2).0.5KCl.3.25H(2)O (1) or PuO2(IO3)(2).0.5KCl.2.5H(2)O (2). The neutral layers in compounds 1 and 2 are isostructural with NPO2(IO3)(2).H2O and PuO2(IO3)(2).H2O, respectively. The Np and Pu centers are found in distorted pentagonal bipyramidal [AnO(7)] environments that are formed from the ligation of NpO22+ or PuO22+ cations by iodate anions. There are two crystallographically unique pyramidal iodate anions in 1 and 2. One of these anions utilizes all three oxygen atoms to simultaneously bridge three neptunyl or plutonyl units. The second anion only bridges two actinyl units and has a terminal oxo atom. The bridging of the actinyl cations by iodate anions creates neutral (2)(infinity)[AnO(2) (IO3)(3)] (An = Np, Pu) sheets that are separated by K+ cations, Cl- anions, and water molecules. Crystallographic data (203 K, MoKalpha, lambda = 0.71073): 1, monoclinic, space group C2/c, a = 21.537(5)Angstrom, b = 11.670(3) Angstrom c = 7.315(2) Angstrom, beta = 93.033(4)degrees, Z = 4: R(F) = 5.43% for 136 parameters with 1309 reflections with I > 2sigma(I); 2, monoclinic, space group C2/c, a = 21.570(4) Angstrom, b = 11.656(2) Angstrom, c = 7.348(2) Angstrom, beta = 94.00(3), Z = 4, R(F) = 4.92% for 148 parameters with 1317 reflections with I > 2sigma(I). (C) 2003 Elsevier Inc. All rights reserved.