Вид документа : Статья из журнала Шифр издания : 54/Z 18 Автор(ы) : Zainullina V. M., Polyakov E. V., Maksimova L. G. Заглавие : Electronic Structures, Chemical Bonding, and Defect Formation in Mixed Cyanoferrates M2Cu[Fe(CN)6] (M=Na, K, Rb, and Cs) Место публикации : Russian Journal of Coordination Chemistry. - 2007. - Vol. 33, № 7. - С. 493-500: il. Примечания : Bibliogr. : p. 500 (18 ref.) ISSN: 1070-3284 ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Ключевые слова (''Своб.индексиров.''): цианоферраты--щелочные металлы Аннотация: The effect of the alkali metal nature on the electronic structures and chemical bonding in mixed cyanoferrates M2Cu[Fe(CN)6](M = Na, K, Rb, and Cs) was studied by ab initio tight-binding linear muffin-tin orbital (TB-LMTO) method (in the spin-polarized implementation) and the extended Hückel molecular orbital (EHMO) method. It was found that the X-ray photoelectron spectra of the ferrimagnetic compounds Na2Cu[Fe(CN)6] (I),K2Cu[Fe(CN)6] (II),Rb2Cu[Fe(CN)6](III), and Cs2Cu [Fe(CN)6](IV) are similar. The magnetic moments on Cu2+ and iron ions remain virtually constant in compounds I–IV(μ(Cu)≈0.9μB,μ(Fe)−0.06μB). Analyses of the electron density maps and the bond overlap populations showed that the cubic frameworks of cyanoferrates are built from stable fragments …–Fe–C≡N–Cu–…. The bond strength in these fragments decreases substantially in the order C–N→Fe-C→Cu–N and only slightly in the order IV→III→II→I. The calculated total energies of the cyanoferrates Cs2–xCu[Fe(CN)6], CsHCu[Fe(CN)6], and NaHCu[Fe(CN)6] for different concentrations and configurations of defects (cesium vacancies and hydrogen substitution defects) suggest mutual repulsion of defects. This repulsion is responsible for the experimentally observed lowering of the ionic conductivity with an increase in the defect concentration in the mixed cyanoferrates Доп.точки доступа: Polyakov, E. V.; Поляков Евгений Валентинович; Maksimova, L. G.; Максимова Лидия Григорьевна