Stetskiv A. Structural chemistry of silicides, germanides and stannides of alkali and rare earth metals

Isothermal sections of nine ternary systems of La, Tb, Dy}-Li-Si, {La, Nd}-Li-Ge, {Y, Ce, Eu, Tb}-Li-Sn and parts of thirteen phase diagrams of quaternary systems of {La, Sm}-Li-Co-Si, Tm Li Со Sn, La Li Ni Si, {La, Pr, Nd}-Li-Ni-Ge, {La, Tb, Dy, Ho, Er, Tm}-Li-Ni-Sn were built. 131 ternary and quaternary compounds were synthesized for the first time. For 122 of these intermetallic compounds crystal structures were fully defined. Formation of 5 new structural types was found: La2LiGe4Si2, Tm2,2Co6Sn20, TmLi2Co6Sn20, Ce2Li0,39Ni1,61Si2 та La2LiAlGe2. For all analyzed ternary systems the same pattern was observed, the vast majority of the ternary phase is in areas of limited from 30 to 60 at.% content of elements of p-block. It was discovered that increasing the number of components in the system does not increase the number of intermetallic compounds but causes more prevalent the formation of solid solutions. Intermetallic compounds were systematized for the first time basing on the concept of electronic localization as a reason for the formation of chemical bonds. Relying on the crystallochemistry analysis it was found that most of the synthesized compounds through primary metallic bonds have other bonds, for example covalent or ionic. It was established that the ionization of atoms can lead to the formation of structures with monatomic cations/anions, polyatomic polycations/polyanions, and structures with layers of 2D and 3D polycations/polyanions. For some of the compounds general process of lithiation, parameters of hydrogen sorbtion and discharge capacity were studied.