Unique Mixed Valence Behavior of Tantalum and Electronic Structure of the Novel P _1−x Ta _8+x N ₁₃ (X = 0.1–0.15) Using Density Functional Theory and Soft X‐Ray Spectroscopy

In this study, the electronic structure and bonding characteristics of PTaN ( x = 0.1–0.15), a compound featuring a high coordination of phosphorus with six nitrogen atoms, are explored. Soft X‐ray spectroscopy and density functional theory calculations are employed to investigate the material's electronic properties. The analysis reveals that the material exhibits metallic behavior, which can be attributed to the 5 d electronic states of tantalum. It is observed that tantalum exists in mixed valence states, forming two distinct types of TaN bonds: one predominantly covalent and the other with a combination of ionic and covalent characteristics. Both bond types contribute to the metallic properties observed. Additionally, it is found that the valence electrons of tantalum are not fully integrated into the TaN bonds, as supported by electron localization function (ELF) calculations, which show electron localization in narrow channels consisting of three Ta atoms. To the best of our knowledge, we have measured the phosphorus L β 3, β 4 XES and L 1 ‐edge XAS for the first time. These findings enhance one's understanding of the complex electronic structure of PTaN and provide insights into the material's potential applications in electronic devices and electrocatalysis.