C 91 Crystal structures of double vanadates LiCoVO4 and Li0:5Co1:25VO4 / O. N. Leonidova, V. I. Voronin, I. A. Leonidov, R. F. Samigullina, B. V. Slobodin // Journal of Structural Chemistry. - 2003. - Vol. 44, № 2. - P243-247 : il. - Bibliogr. : p. 247 (9 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ВАНАДАТЫ -- ШПИНЕЛИ -- ЭЛЕКТРОННАЯ СТРУКТУРА -- ЛИТИЙ Аннотация: The crystal structures of vanadates Li1-2xCo1+xVO4 with x = 0 and 0:25 have been studied by a full pattern analysis. It has been shown that in cubic spinel LiCoVO4 (space group Fd3m), the 8a tetrahedral sites contain a majority of vanadium and a small amount of lithium; all cobalt, lithium, and a small amount of vanadium occupy the 16d octahedral sites. Li0.5Co1.25VO4 crystals belong to the rhombic system (Imma space group) with unit cell parameters a = 5:939(1) A, b = 5:810(1) A, and c = 8:303(1) A. On substitution of lithium by cobalt according to the scheme 2Li+ -> Co2+ + , half of the lithium and 70% of the vacancies formed are in the 4a octahedral sites, and one-third of lithium and most of cobalt occupy the 4d octahedral sites. The 4e tetrahedral sites are completely occupied by vanadium and lithium in a ratio of 0:92=0:08. The interatomic distances in LiCoVO4 and Li0.5Co1.25VO4 are calculated, and the sizes of lithium ion transport channels are evaluated Полный текст |