Abstract:Electronegativity is a well-known property of atoms and substituent groups. Because there is no direct way to measure it, establishing a useful scale for electronegativity often entails correlating it to another chemical parameter; a wide variety of methods have been proposed over the past 80 years to do just that. This work reports a new approach that connects electronegativity to a spectroscopic parameter derived from resonant inelastic x-ray scattering. The new method is demonstrated using a series of chlor… Show more
“…Building on previous studies, RIXS results give additional information on the O K-edge indicating rearrangement of the O 2p band, suggesting a change in electronegativity of the oxygen Error bars are ± 10% of the respective value, which has been estimated by evaluating the pre-edge intensities for normalizations to five different points around the normalization point of the presented TEY spectrum of the pristine sample and thus accounting for variations due to its noise level anion 55 . The difference in the electronic character in oxygen are labelled as O l , O m and O n .…”
Sodium-ion batteries have become a potential alternative to Li-ion batteries due to the abundance of sodium resources. Sodium-ion cathode materials have been widely studied with particular focus on layered oxide lithium analogues. Generally, the capacity is limited by the redox processes of transition metals. Recently, however, the redox participation of oxygen gained a lot of research interest. Here the Mg-doped cathode material P2-Na 0.56 Mg 0.04 Ni 0.19 Mn 0.70 O 2 is studied, which is shown to exhibit a good capacity (ca. 120 mAh/g) and high average operating voltage (ca. 3.5 V vs. Na + /Na). Due to the Mg-doping, the material exhibits a reversible phase transition above 4.3 V, which is attractive in terms of lifetime stability. In this study, we combine X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy techniques to shed light on both, cationic and anionic contributions towards charge compensation.
“…Building on previous studies, RIXS results give additional information on the O K-edge indicating rearrangement of the O 2p band, suggesting a change in electronegativity of the oxygen Error bars are ± 10% of the respective value, which has been estimated by evaluating the pre-edge intensities for normalizations to five different points around the normalization point of the presented TEY spectrum of the pristine sample and thus accounting for variations due to its noise level anion 55 . The difference in the electronic character in oxygen are labelled as O l , O m and O n .…”
Sodium-ion batteries have become a potential alternative to Li-ion batteries due to the abundance of sodium resources. Sodium-ion cathode materials have been widely studied with particular focus on layered oxide lithium analogues. Generally, the capacity is limited by the redox processes of transition metals. Recently, however, the redox participation of oxygen gained a lot of research interest. Here the Mg-doped cathode material P2-Na 0.56 Mg 0.04 Ni 0.19 Mn 0.70 O 2 is studied, which is shown to exhibit a good capacity (ca. 120 mAh/g) and high average operating voltage (ca. 3.5 V vs. Na + /Na). Due to the Mg-doping, the material exhibits a reversible phase transition above 4.3 V, which is attractive in terms of lifetime stability. In this study, we combine X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy techniques to shed light on both, cationic and anionic contributions towards charge compensation.
“…In fact, TFY measurements are seemingly essentially sensitive to the large MLCT to these ligands, which might explain the similarity of the corresponding XA spectra although NO is described in the literature as a much stronger ligand than O 2 . 27 For MbCO and MbCN, a strong fluorescence quenching happens which reflects additional charge transfers. For MbCN in particular, an increase in MLCT might contribute to lower the intensity of the most prominent spectral feature at the L 3edge ( Fig.…”
Iron L-edge X-ray absorption spectra of the active centre of myoglobin in the met-form, in the reduced form and upon ligation to O2, CO, NO and CN are presented. The strength of ligation with the iron centre is finger-printed through the variation of the L3 : L2 intensity ratio. Charge Transfer Multiplet calculations are performed and give qualitative information about oxidation states as well as charge transfer.
“…However, χR, and ΣχR may also relate to the substructures (shake-up, shake-down, and multiplet splitting) of the Mn 2p3/2 and Fe 2p3/2 photoelectron lines [32].…”
Abstract:A series of ferrocenyl-functionalized β-diketonato manganese(III) complexes, [Mn(FcCOCHCOR) 3 ] with R = CF 3 , CH 3 , Ph (phenyl) and Fc (ferrocenyl) was subjected to a systematic XPS study of the Mn 2p 3/2 and Fe 2p 3/2 core-level photoelectron lines and their satellite structures. A charge-transfer process from the β-diketonato ligand to the Mn(III) metal center is responsible for the prominent shake-up satellite peaks of the Mn 2p photoelectron lines and the shake-down satellite peaks of the Fe 2p photoelectron lines. Multiplet splitting simulations of the photoelectron lines of the Mn(III) center of [Mn(FcCOCHCOR) 3 ] resemble the calculated Mn 2p 3/2 envelope of Mn 3+ ions well, indicating the Mn(III) centers are in the high spin state. XPS spectra of complexes with unsymmetrical β-diketonato ligands (i.e., R not Fc) were described with two sets of multiplet splitting peaks representing fac and the more stable mer isomers respectively. Stronger electron-donating ligands stabilize fac more than mer isomers. The sum of group electronegativities, Σχ R , of the β-diketonato pendant side groups influences the binding energies of the multiplet splitting and charge transfer peaks in both Mn and Fe 2p 3/2 photoelectron lines, the ratio of satellite to main peak intensities, and the degree of covalence of the Mn-O bond.
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