Theoretical Assignment of Oxidation State of Uranium in Binary, Ternary, and Quaternary Tellurides

The recent breakthrough in the discovery of nearly ferromagnetic spintriplet superconductivity UTe2 has attracted vivid investigations regarding its physical properties; however, the fundamental-chemistry understanding of UTe2 and other U tellurides remains lacking. Hereby, a systematic first-principles calculation is conducted on the behavior of U binary, ternary, and quaternary tellurides, with particular focus on the rigorous assignment of quantum-mechanical oxidation state (OSqm) of U ions by counting the Sf orbital occupation number. The results show the trend and variation of U OSqm and disclose the correlation among OSqm, structure, and composition. Interestingly, OSqm behavior in tellurides is rather dissimilar from that in oxides, which is mainly due to the relatively weak U-Te bonding interaction and strong tendency of forming Te clusters or chains in solids. Among the considered tellurides, the highest OS(qm )of U ions is U4+ instead of the formally highest valent U6+ in the ionic limitation; the only exception occurs on molecular crystal U(TeOF5)(6) in which U adopts U6+ because of the absence of U-Te bonds and the saturation of dominating U-O bonds.

Automated summary

A systematic first-principles calculation was conducted on the behavior of U binary, ternary, and quaternary tellurides, focusing on the quantum-mechanical oxidation state of U ions and its correlation with structure and composition. The highest quantum oxidation state of U ions in tellurides was found to be U4+ instead of the formally highest valent U6+ under ionic limitations.