High-pressure synthesis of novel transition metal polynitrides

• Applicant: Professor Dr. Maxim Bykov
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Mineralogy, Petrology and Geochemistry
• Term: Funded in 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417849358

The high-pressure chemistry of nitrogen became a hot topic in the recent years after several breakthrough discoveries: the synthesis of alkali earth metal diazenides, transition metal pernitrides, and polymeric nitrogen allotrope cg-N at high-pressure high-temperature conditions. An application of pressure opens a straightforward synthetic route to new inorganic materials with covalent N-N bonds through the simple reaction M + 1/2 x N2 -> MNx, where M can be almost any element from the periodic table. Theoretical calculations predict over a hundred of polynitrides that may have important chemical and physical properties like high hardness, low compressibility, high energy density etc., however up to now the experimental information is very limited. The goal of the project is the systematic study the formation of transition metal polynitrides (with focus on Re, Os, W, Cr, Ru, Ti, Zr, Hf) at high-pressure-high temperature conditions, and study their crystal chemistry and physical properties. In the present project, polynitrides will be synthesized at high pressures and temperatures in laser-heated diamond anvil cells in a direct reaction between metal and nitrogen. By the common term “polynitrides” or “polynitrogen compounds” we mean compounds containing polymeric and oligomeric chains, ring structures, or 3D networks, built from nitrogen atoms. The resulting materials will be studied employing a range of advanced complimentary techniques: single-crystal X-ray diffraction (XRD), Raman spectroscopy, FIB-assisted analysis of recovered materials, and theoretical calculations. The ultimate aim of the project is to reveal relations between synthetic conditions, chemical bonding, structure, and properties of polynitrides of different metals, and to formulate crystal chemical principals governing formation and behavior of polynitrides at extreme conditions.

• DFG Programme: Research Grants