The thesis is devoted to the study of quasibinary systems for the purpose of solubility of the fourth component in equiatomic compounds, concentration and structural characteristics of solid solutions, crystal chemical features of new ternary and tetrar compounds, measuring physical properties and electronic structure calculations of some of them.
The phase composition of alloys were characterized by means of X-ray powder diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy, the crystal structures of the phases were established by the methods of X-ray structural analysis. According to the results of experimental studies, the solubility limits of the fourth component in the starting compounds, the length and structure of the phase components of solid solutions in quasi-double systems RENiIn1-xAlx (RE = La, Ce), RETIn1-xGax (RE = La, Ce; T = Ni, Cu) and RENiIn1-xGex (RE = La, Ce) at 873 K were determined.
In the CeNiIn1-xMx systems (M = Al, Ga) the formation of continuous solid solutions with a structure of the ZrNiAl type was established and the crystal structure of 3 new tetrar compounds was determined. The LaNiIn1-xMx (M = Al, Ga), RENiIn1-xGex and RECuIn1-xGax (RE = La, Ce) systems based on equiatomic compounds are characterized by the formation of twelve limited solid substitution solutions with structures of the types of starting compounds.
The solubility of germanium in REPtIn compounds (RE = La, Ce) was investigated, the formation of limited solid solutions of REPt1-0,7Ge0-0,3In composition was established, and the nature of changes of unit cell parameters and atomic parameters in structures was analyzed.
For the first time, the crystal structure of 10 ternary aluminides, 6 ternary indides, 4 ternary germanides, and the tetrary compound LaNiIn0,43Ga0,57, four of which i9-CeNi2,28Al2,72, EuPt2Al3, EuIr2Al4, Ca0,265Yb0,735Ni3Ge2 are the first representatives of new structure types of IMC.
Measurements of magnetic and electrotransport properties of compounds SmPt2In2, LaNiGe, and LaNiIn0,5Ga0,5 were performed. The compounds LaNiGe and LaNiIn0,5Ga0,5 were found to be typical Pauli paramagnets, and the compound SmPt2In2 shows an antiferromagnetic exchange interaction between the magnetic moments localized on Sm atoms. All investigated compounds are characterized by the metallic nature of electrical conductivity.
Quantum mechanical calculations of the electronic structure were performed for compounds La3Ni4Al2, i9-PrNi2,09Al2,91, i7-PrNi2,31Al2,69, i3-YbNi2,31Al2,69, i3-ErNi2,23Al2,77, EuPt2Al3, EuIr2Al4, LaNiGe, SmPt2In2, LaIrIn and YbIrIn.
The nature of the interaction of components in the studied systems, its features are discussed, and it is established that the main influence on it is the size of atoms and electronic structure of interchangeable p-elements and structural characteristics of the initial compounds. Topological and crystal chemical analyzes were performed for compounds with the investigated crystal structure and relationships with known structural types were established.
