Formation of Metal Oxyfluorides from Specific Metal Reactions with Oxygen Difluoride: Infrared Spectroscopic and Theoretical Investigations of the OScF₂ Radical and OScF with Terminal Single and Triple ScO Bonds

Abstract

The scandium oxydifluoride free radical, OScF(2), is produced by the spontaneous, specific reaction of laser ablated Sc atoms with OF(2) in solid argon and characterized by using matrix infrared spectroscopy and theoretical calculations. The OScF(2) molecule is predicted to have C(2v) symmetry and a (2)B(2) ground state with an unpaired electron located primarily on the terminal oxygen atom, which makes it a scandium difluoride molecule coordinated by a neutral oxygen atom radical in forming the Sc-O single bond. The closed shell singlet OScF molecule with an obtuse bent geometry has a much shorter Sc-O bond of 1.682 Å than that of the OScF(2) radical (1.938 Å) on the basis of B3LYP calculations. The Sc-O bond in OScF consists of two covalent bonds and a dative bond in which the oxygen 2p(π) lone pair donates electron density into an empty Sc 3d orbital thus forming a triple oxo bond. Density functional calculations suggest it is highly exothermic for fluorine transfer from OF(2) to scandium, which favors the formation of the OScF(2) radical species as well as the OScF molecule after fluorine loss.

Raman Spectroscopic and Theoretical Study of Scandium Fluoride and Oxyfluoride Anions in Molten FLiNaK

“…As shown in Figure S5, the Sc–O and Sc–F bonds are elongated as more F – is coordinated to the scandium center. The Sc–O bond lengths are 1.871 and 1.806 Å, respectively, which are between the values of ScO double (1.682 Å) and Sc–O single (1.938 Å) bonds identified in neutral scandium oxyfluorides . This is in agreement with the fact that the Sc–O stretches for ScOF 4 3– and ScOF 3 2– lie between those of neutral ScOF 2 and ScOF molecules.…”

Structures and Properties of the Products of the Reaction of Lanthanide Atoms with H2O: Dominance of the +II Oxidation State

“…The weak O–F bond precludes the formation of FLnOF, which can either eliminate the F or rearrange to form OLnF 2 . Such is also the case for the group 3 and 4 metals. , …”

“…Such is also the case for the group 3 and 4 metals. 66,67 As in the Ln + OF 2 reactions, 7 the LnO stretch serves as a diagnostic of the quality of the wave function. Although spin polarization solutions were found with slightly lower energies than a higher spin solution, the stretching frequencies did not match the experiments.…”

Infrared Spectroscopic and Theoretical Studies on the OMF2 and OMF (M = Cr, Mo, W) Molecules in Solid Argon

“…On the basis of the observation of one terminal Cr–O and two F–Cr–F stretches, the new molecule is identified as OCrF 2 . The lack of 18 O shift for the 735.3 cm –1 band is due to the low participation of oxygen in this antisymmetric vibrational mode, as in the cases of OScF 2 and OTiF 2 . , …”

“…The OF absorption decreased on annealing and increased when the sample was subjected to broad band irradiation (λ > 220 nm). Other weak absorptions due to O 3 , CO 2 , and SiF 4 were present in the spectra right after sample deposition as well, which were common species in the spectra from the reactions of OF 2 and laser-ablated metal atoms. − ,− All of the new product bands observed in the experiments with OF 2 and 18 OF 2 samples are listed in Table .…”