Mass spectrometric and FTIR spectroscopic identification of FeF4 molecules in gaseous phase

A Matrix‐Isolation and Quantum‐Chemical Investigation of FeF4

“…Furthermore, no quantum-chemical calcu-lations were made to support the assignment of the band or the suggested structure. [12] Herein, we present the IR spectra of matrix-isolated iron tetrafluoride combined with state-of-the-art quantum-chemical calculations, which strongly support our interpretation of the spectra.…”

“…The present findings support the previous tentative assignment of the 758.5 cm À1 argon matrix band to a higher iron fluoride. [12] Although the FeF 4 molecule is computed to be stable in the gas phase under standard conditions, its existence as bulk material seems improbable, as shown by a Born-Fajans-Haber cycle. Nevertheless, it might be stabilized in aHF solutions, but the calculation of solvation energies are beyond the scope of the present study.…”

“…In a combined mass-spectrometric and matrix-isolation investigation, FeF 3 was reacted with the fluorine atom donor CeF 4 , and the existence of FeF 4 has been postulated based on the relative abundance of [FeF 3 ] + and [FeF 2 ] + fragments in the mass spectrum and a new weak IR absorption at 758.5 cm À1 in an argon matrix, which could not be assigned to one of the lower fluorides. [12] As no other related band was observed, FeF 4 was assumed to have a highly symmetric, either square-planar or tetrahedral structure, which is highly improbable for a d 4 system for which a Jahn-Teller distortion is to be expected. Furthermore, no quantum-chemical calcu-lations were made to support the assignment of the band or the suggested structure.…”

A Matrix‐Isolation and Quantum‐Chemical Investigation of FeF4

“…Both FeF 2 and FeF 3 are well‐known and intensively studied compounds,8–11 whereas the next in line, FeF 4 , has so far eluded unambiguous identification. In a combined mass‐spectrometric and matrix‐isolation investigation, FeF 3 was reacted with the fluorine atom donor CeF 4 , and the existence of FeF 4 has been postulated based on the relative abundance of [FeF 3 ] + and [FeF 2 ] + fragments in the mass spectrum and a new weak IR absorption at 758.5 cm −1 in an argon matrix, which could not be assigned to one of the lower fluorides 12. As no other related band was observed, FeF 4 was assumed to have a highly symmetric, either square‐planar or tetrahedral structure, which is highly improbable for a d 4 system for which a Jahn–Teller distortion is to be expected.…”

Interplay of thermochemistry and Structural Chemistry, the Journal (volume 22, 2011, issues 1–3) and the discipline

“…Computational results for small oligomers of FeCl 2 (n = 3, 4) have shown that the stability of tetramer is consistent with the crystal structure of FeCl 2 . Besides the above Fe(II) and Fe(III) halides, other iron halides that have thermochemically studied in the gas phase include FeF [92], Fe 2 F 5 [93], and FeF 4 [94].…”