Study of New Ternary Rare-Earth Intermetallic Germanides with Polar Covalent Bonding

The thesis focuses on the syntheses, structural characterizations and chemical bonding analyses for several ternary RMGe (R = rare earth metal; M = another metal) intermetallics. The challenges in understanding the main interactions governing the chemistry of these compounds, which lead to our inability to predict their formation, structure and properties, are what provided the motivation for this study. In particular, the R2MGe6 (M = Li, Mg, Al, Cu, Zn, Pd, Ag), R4MGe10-x (M = Li, Mg), R2Pd3Ge5, Lu5Pd4Ge8, Lu3Pd4Ge4 and Yb2PdGe3 phases were synthesized and structurally characterized. Much effort was put into the stabilization of metastable phases, employing the innovative metal flux method, and into the accurate structure solution of twinned crystals. Cutting-edge position-space chemical bonding techniques were combined with newmethodologies conceived to correctly describe the GeM, GeLa and also LaM polar-covalent interactions for the La2MGe6 (M = Li, Mg, Al, Cu, Zn, Pd, Ag) series. The present results constitute a step forward in our comprehension of ternary germanide chemistry as well as providing a good playground for further investigations.

Nominated as an outstanding Ph.D. thesis by the Max Planck Institute for Chemical Physics of Solids, Dresden, Germany Provides a didactic overview of the main experimental and theoretical methodologies employed nowadays in the field of intermetallic chemistry Presents in detail the synthetic procedures, metallographic characterization and crystal structure determination of several ternary rare-earth germanides Discusses chemical bonding using state of the art position-space techniques proposing also new and sophisticated tools

Autorentext

Riccardo Freccero received his M.Sc. and Ph.D. in Chemistry at the University of Genoa, Italy, in 2015 and 2018, respectively. The Ph.D. thesis was performed under the supervision of Prof. Adriana Saccone (University of Genoa) and Dr. Frank R. Wagner (Max Planck Institute for Chemical Physics of Solids, Dresden, Germany - MPI-CPfS), focusing on the synthesis, crystal structure determination and chemical bonding analysis of ternary intermetallic germanides. He is now working as a post-doctoral researcher in the ChemBond group of the Chemical Metals Science department, headed by prof. Yuri Grin, at the MPI-CPfS.

Inhalt
Introduction.- Experimental Methods.- Theoretical Methods.- The R2MGe6 (R = rare earth metal; M = another metal) Compounds: An Experimental and Theoretical Study on Their Synthesis, Crystal Structure and Chemical Bonding.- On the Existence, Crystal Structure and Physical Properties of R2Pd3Ge5 (R = rare earth metal) Intermetallic Germanides.- Lu5Pd4Ge8, Lu3Pd4Ge4 and Yb2PdGe3: Three More Germanides among Polar Intermetallics.