Crystal structure and spectral properties of complexes of tetravalent Th, U, Np and Pu nitrates with trimethyl phosphate and dimethyl phosphate

摘要

Single crystals of [Th(TMP)_6(NO_3)_2] [Th(TMP)_2(NO_3)_5]_2 (1), [Th(TMP) _4(NO_3)_3][Th(TMP)_2(NO _3)_5] (2), [U(DMP)_3(NO_3)] (3), [Np(DMP)_3(NO_3)] (4), and [Pu(DMP)_2(NO _3)_2(H_2O)]H_2O (5) have been synthesized and their structures have been determined by X-ray analysis. IR and optical spectra of polycrystalline compounds 3 and 4 were measured at room temperature. The Th(IV) is crystallized as two complexes with TMP molecular ligands and NO_3 anions in coordination environment. The Th atoms in cationic moieties of 1 and 2 are characterized by coordination number of 10 and in the anionic moieties by coordination number of 12. Compounds of U(IV), Np(IV) and Pu(IV) were obtained with two different anions (NO_3 and DMP) in coordination environment of the central atom. U(IV) and Np(IV) compounds are isostructural and the main motif of structure is made of infinite chains of [An(DMP)_3(NO_3)]_n, twisted around hexagonal axes. In the structure of Pu(IV) the main structural motif is made of infinite chains [Pu(DMP)_2(NO_3)_2(H_2O)] _n, extending along the b axis. The coordination numbers of An(IV) are equal to 8 for U and Np, and 9 for Pu. The difference in the structure and composition of formed compounds Th and U, Np, Pu could be explained by hydrolysis of TMP at the synthesis conditions.