New structures and properties of YF₃ and YF₆ under high pressure

Exploring new structures and properties of matter is a central topic in condensed matter physics. In this work, first-principles calculations and structure prediction methods were employed to investigate fluorine-rich yttrium compounds. Two new stable phases, Pmmn-YF₃ and Amm2-YF₆, have been identified under high pressure. Pmmn-YF₃ is stable over a pressure range of 50 GPa to 500 GPa, and Amm2-YF₆ remains stable at pressures beyond 429 GPa. Analysis of the band structure, density of states (DOS), and Bader charge for these two stable compounds reveals that Pmmn-YF₃ is an insulator and Amm2-YF₆ is a metal, elucidating their chemical bonding characteristics. F–F bond lengths and Bader charge analysis confirm the +3 oxidation state of yttrium in the molecular crystal YF₃ and the crystal structure YF₆. Our work provides a valuable theoretical foundation for elucidating the properties of the rare earth transition metal yttrium.