Identification of a Ternary Nitride Ti₁₀Cu₃N₄ with a Unique Structure Type

This study presents the synthesis and detailed structural analysis of the ternary nitride Ti₁₀Cu₃N₄. Initially identified as Ti₃CuN within the Ti-Cu-N ternary phase diagram, its crystal structure remained unresolved and was characterized solely as belonging to the tetragonal crystal system. Through a comprehensive structural analysis, this study proposes a revised stoichiometry as Ti₁₀Cu₃N₄; its crystal structure represents a previously unreported structure type within the P4₂/mnm space group. Its atomic arrangement was elucidated through a combination of X-ray powder diffraction profile analysis and density functional theory calculations, corroborated by neutron diffraction studies. Furthermore, the hydrogen storage properties of Ti₁₀Cu₃N₄ were characterized, demonstrating a hydrogen absorption capacity of approximately 0.6 wt % with desorption occurring in the temperature range of 200-550 °C.