Synthesis and Crystal Chemistry of Rare-Earth Polycarbides at Pressures above 150 GPa in Laser-Heated DACs

Carbides form a family of compounds important in science and technology due to their interesting chemical, mechanical, electrical, magnetic and optical properties. Structural variations as a function of composition and external parameters (pressure and temperature) often result in formation of carbides with various types of chemical bonding, as well as with fascinating crystal chemistry. The high-pressure chemistry and physical properties of rare earth metal carbides are almost unknown. Here we propose to investigate the Ln-C (Ln = La, Nd, Sm, Gd, Dy, Yb) systems up to 220 GPa by single crystal X-ray diffraction (SC-XRD). The diamonds are suggested to be used as the source of carbon (as the most enriched with carbon material). The main objectives of this proposal are a synthesis of new Ln-C compounds at multimegabar pressure, characterization of their crystal chemistry, tests of theoretical predictions, and search for regularities in lanthanides carbides chemistry.