Exploring the Limits of Transition-Metal Fluorination at High Pressures
Journal article, 2020

Fluorination is a proven method for challenging the limits of chemistry, both structurally and electronically. Here we explore computationally how pressures below 300 GPa affect the fluorination of several transition metals. A plethora of new structural phases are predicted along with the possibility for synthesizing four unobserved compounds: TcF7, CdF3, OsF8, and IrF8. The Ir and Os octaflourides are both predicted to be stable as quasi-molecular phases with an unusual cubic ligand coordination, and both compounds formally correspond to a high oxidation state of +8. Electronic-structure analysis reveals that otherwise unoccupied 6p levels are brought down in energy by the combined effects of pressure and a strong ligand field. The valence expansion of Os and Ir enables ligand-to-metal F 2p -> M 6p charge transfer that strengthens M-F bonds and decreases the overall bond polarity. The lower stability of IrF8, and the instability of PtF8 and several other compounds below 300 GPa, is explained by the occupation of M-F antibonding orbitals in octafluorides with a metal-valence-electron count exceeding 8.


structural prediction

oxidation states

oxidizing agent

chemical bonding


Jianyan Lin

Northeast Normal University

Xin Du

Northeast Normal University

Martin Rahm

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Hong Yu

Northeast Normal University

Haiyang Xu

Northeast Normal University

Guochun Yang

Northeast Normal University

Angewandte Chemie - International Edition

1433-7851 (ISSN) 1521-3773 (eISSN)

Vol. 59 23 9155-9162

Subject Categories

Inorganic Chemistry

Theoretical Chemistry

Condensed Matter Physics





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