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Exploring the Limits of Transition‐Metal Fluorination at High Pressures
Author(s) -
Lin Jianyan,
Du Xin,
Rahm Martin,
Yu Hong,
Xu Haiyang,
Yang Guochun
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202002339
Subject(s) - antibonding molecular orbital , valence (chemistry) , chemistry , transition metal , metal , ligand (biochemistry) , atomic orbital , crystallography , ligand field theory , chemical physics , computational chemistry , electron , ion , physics , organic chemistry , biochemistry , receptor , quantum mechanics , catalysis
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: TcF 7 , CdF 3 , OsF 8 , and IrF 8 . 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 IrF 8 , and the instability of PtF 8 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.