ИСТИНА

Ordered intermetallic compounds are a fascinating object of studies both due to their structural diversity and the variety of physical properties. The very fact of their existence in itself is worth explaining, however, they also often feature complicated structure motifs and convoluted bonding patterns, as well as sometimes unique and potentially useful properties and complicated structure-property relationships. Furthermore, if a 3D intermetallic system is diluted with a typical non-metal, the situation becomes even less straightforward. This concept is showcased well using transition metal-rich mixed group 10 – group 13 chalcogenides and pnictides. The focus of our research is TM3M intermetallics of the Cu3Au or related type (where TM = Ni, Pd, Pt; M – main-group metal) as parent compounds for complex ternary phases. The structural unit of such intermetallics is a main-group metal-centered cuboctahedron of transition metal atoms. The packing of these units may vary, depending on the type of constituents, but the units remain the same. We have produced and characterized a series of ternary chalcogenides and pnictides based on the TM3M-type fragments with structures varying from 2D linear intergrowth structures to open-framework to 3D ones. To gain more insight into their principles of formation and stability, we have studied electronic structures and bonding, both in orbital (COHP) and direct (ELF, ELI-D) space, in ternary compounds and their parent binaries based on the DFT calculations. Along with common features in electronic structures and bonding, the differences in bonding patterns, depending on the type of transition metal, are revealed and discussed. _____________________________________________ ∗ This work was supported by Russian Science Foundation (Grant No. 14-13-01115). The use of the resources of MSU Supercomputer Center is acknowledged.