Synthesis and Structures of Cs_4[(UO_2)_2(C_2O_4)(SO_4)_2(NCS)_2] centre dot 4H_2O and (NH_4)_4[(UO_2)_2(C_2O_4)(SO_4)_2(NCS)_2] centre dot 6H_2O

摘要

Single crystals of Cs_4[(UO_2)_2(C_2O_4)(SO_4)_2(NCS)_2] centre dot 4H_2O (I) and (NH_4)_4[(UO_2)_2(C_2O_4)(SO_4)_2(NCS)_2] centre dot 6H_2O (II) have been synthesized and studied by X-ray diffraction. The crystals of both compounds are ortho-rhombic with the space group Pbam, Z = 2, and unit cell parameters a = 12.0177(3) k,b = 18.6182(5) A c = 6.7573(10) k,R = 0.0376 (I); a = 11.6539(9) A, b = 18.3791(13) k,c = 6.7216(5) k,R = 0.0179 (II). The main structural units of crystals I and II are [(UO_2)_2(C_2O_4)(SO_4)_2(NCS)_2]~(4-) chains belonging to the crystal-chemical group A_2K~(02)B_2~2M_2~1 (A = UO_2~(2+), K~(02) = C_22O_4~(2-), B~2 = SO_4~(2-), M~1 = NCS~-) of the uranyl complexes. The uranium-containing chains are joined into a three-dimensional framework due to a system of electrostatic interactions with the cesium or ammonium ions in the structure of I. In the structure of II, this framework is additionally stabilized by hydrogen bonds involving the outer-sphere water molecules and ammonium ions.