An Interacting Quantum Atoms Analysis of the Metal-Metal Bond in [M 2 (CO) 8 ] n Systems Davide Tiana, ∗,† E. Francisco, ‡ P. Macchi, ¶ Angelo Sironi, § and A. Martín Pendás ‡ Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK, Departamento de Química Física y Analítica. Facultad de Química. Universidad de Oviedo. 33006-Oviedo. Spain., Department of Chemistry and Biochemistry. University of Bern. Switzerland, and Department of Chemistry. University of Milan. Via Golgi 19. 20133 Milan. Italy. E-mail: davide.tiana@materials.ox.ac.uk Abstract The metal-metal interaction in policarbonyl metal clusters remains one of the most challenging and controversial issues in metal-organic chemistry, being at heart of a generalized understanding of chemical bonding and of specific applications of these molecules. In this work, the interacting quantum atoms (IQA) approach is used to study the metal-metal interaction in dimetal polycarbonyl dimers, analysing bridged (Co 2 (CO) 8 )), semi-bridged ([FeCo(CO) 8 ] − ) and unbridged (Co 2 (CO) 8 , [Fe 2 (CO) 8 ] 2− ) clusters. In all systems, a delocalized covalent bond is found to occur, involving the metals and the carbonyls, but the global stability of the dimers mainly originates from the coulombic attraction between the metals and the oxygens. * To whom correspondence should be addressed † Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK ‡ Departamento de Química Física y Analítica. Facultad de Química. Universidad de Oviedo. 33006- Oviedo. Spain. ¶ Department of Chemistry and Biochemistry. University of Bern. Switzerland § Department of Chemistry. University of Milan. Via Golgi 19. 20133 Milan. Italy. 1 source: https://doi.org/10.7892/boris.73112 | downloaded: 2.6.2020