S 98 Synthesis of the LnNb7O12 (Ln = La, Ce, Pr) Discrete-cluster compounds [Text] / O. G. Reznitskikh, V. G. Zubkov, N. I. Lobachevskaya, A. P. Tyutyunnik, V. G. Bamburov // Inorganic Materials. - 2006. - Vol. 42, № 5. - P532-536. - Bibliogr. : с. 536 (9 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКСИДЫ ЛАНТАНОИДОВ -- КЛАСТЕРЫ ДИСКРЕТНЫЕ -- СТЕХИОМЕТРИЯ -- ОКСОНИОБАТЫ Аннотация: The new compounds CeNb7O1n PrNb7O12, isostructural with LaNb7O12, have been synthesized and characterized by x-ray diffraction. The structures of the LnNb7O12(Ln = La, Ce, Pr) compounds have space group P21/c(Z= 4), with lattice parameters a= 10.764(2), 10.743(2), 10.738(4) Å; b= 9.192(2), 9.146(2), 9.137(3) Å; c= 10.313(2), 10.304(2), 10.303(3) Å; and β= 104.25(2)°, 104.31(2)°, and 104.21(3)°, respectively. The reduction in the lattice parameters of LnNb7O12in going from La to Pr correlates with the ionic radii of Ln:r(La3+) >r(Ce3+) >r(Pr3+). In the Nd(Sm)–Nb–O systems, phases of stoichiometry LnNb7O12 have not been obtained Полный текст |