Synthesis, X-ray Diffraction Analysis, and Spectral Properties of the Double Cesium Neptunium Nitrite Cs_3[NpO_2(NO_2)_4] and Thiocyanate Cs_4[NpO_2(NCS)_5]·2.5H_2O

摘要

The structure and spectral properties of the Np(V) nitrite and thiocyanate complexes Cs_3[NpO_2· (NO_2)_4] and Cs_4[NpO_2(NCS)_5]·2.5H_2O were studied. In the structure of Cs_3[NpO_2(NO_2)_4], two independent Np atoms occupy special positions and have similar oxygen surrounding in the form of hexagonal bipyramids. The equatorial planes of the bipyramids are formed by the oxygen atoms of four independent nitrite ions, two of which are bonded in the monodentate fashion and two, in the bidentate fashion. There are three independent Cs atoms in the structure; their coordination surrounding is constituted by the O atoms of NpO_2~+ cations and NO_2~- anions. The Cs(1) atom has the coordination surrounding in the form of a 9-vertex polyhedron; Cs(2), in the form of a 10-vertex polyhedron; and Cs(3), in the form of an 8-vertex polyhedron. In the structure of Cs_4[NpO_2(NCS)_5]·2.5H_2O, the Np atom has the coordination surrounding in the form of a pentagonal bipyramid with the equatorial plane formed by the nitrogen atoms of five independent NCS~- ions. There are four independent Cs cations in the structure; their coordination surrounding is constituted by the O, N, C, and S atoms. The surrounding of the Cs(1), Cs(2), Cs(3), and Cs(4) atoms can be described as 11-, 14-, 12-, and 9-vertex polyhedra, respectively. The IR and electronic absorption spectra of the compounds are presented.