Na4IrO4: Square‐Planar Coordination of a Transition Metal in d5 Configuration due to Weak On‐Site Coulomb Interactions |
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| Authors: | Dr. Sudipta Kanungo Dr. Binghai Yan Patrick Merz Prof. Dr. Claudia Felser Prof. Dr. Martin Jansen |
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| Affiliation: | 1. Max‐Planck‐Institut für Chemische Physik fester Stoffe, 01187 Dresden (Germany);2. Max‐Planck‐Institut für Physik komplexer Systeme, 01187 Dresden (Germany);3. Max‐Planck‐Institut für Festk?rperforschung, 70569 Stuttgart (Germany) |
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| Abstract: | Local environments and valence electron counts primarily determine the electronic states and physical properties of transition‐metal complexes. For example, square‐planar coordination geometries found in transition‐metal oxometalates such as cuprates are usually associated with the d8 or d9 electron configuration. In this work, we address an unusual square‐planar single oxoanionic [IrO4]4? species, as observed in Na4IrO4 in which IrIV has a d5 configuration, and characterize the chemical bonding through experiments and by ab initio calculations. We find that the IrIV center in ground‐state Na4IrO4 has square‐planar coordination geometry because of the weak Coulomb repulsion of the Ir‐5d electrons. In contrast, in its 3d counterpart Na4CoO4, the CoIV center is tetrahedrally coordinated because of strong electron correlation. Na4IrO4 may thus serve as a simple yet important example to study the ramifications of Hubbard‐type Coulomb interactions on local geometries. |
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| Keywords: | ab initio calculations coordination geometry electronic structure oxometalates transition metals |
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