Copper ground state electronic configuration

Exceptions to predicted configurations You can use the aufbau diagram to write correct ground-state electron configurations for all elements up to and including vanadium, atomic number 23. However, if you were to proceed in this manner, your configurations for chromium, [Ar]4s 3d, and copper, [Ar]4s 3d, would prove to be incorrect. The correct configurations for these two elements are ... 

Chromium (Cr) and copper (Cu) are the first two elements for which the orbital filling order given in expression (8.22) fails to give the correct prediction for the ground-state electron configuration. 

There are several prerequisites which have to be fulfilled for the one electron ECP approach to be applicable. In the case of metal clusters the atomic configuration must be known, i.e. one must safely be able to assume a dns2 or a drL+1s1 configurations on the atoms in the cluster. The d orbitals should not form covalent bonds neither within the cluster nor between the cluster and the adsorbate. Ferromagnetic metals and copper are likely to have these properties. For other metals this is not so clear. Indications are that e.g. the ground state of the Pts cluster is low spin with developed covalent intra cluster d-d bonds[22]. 

Copper(II) has a 3d9 electronic configuration. In principle, pure octahedral and tetrahedral symmetries can never be observed because Jahn-Teller distortions (see Section 3.3.1) remove the orbital degeneracy of the ground state. The separation of the electronic energy levels depends on the coordination number and stereochemistry, as well as on the nature of the ligands. However, the ground state orbital is always well isolated from the excited states, and therefore the electronic relaxation mechanisms are relatively inefficient. Copperfll) complexes have thus relatively sharp EPR signals, and it is often possible to record these spectra at room temperature. 

If these substituents are not introduced to the ligand, the lifetime of the excited state becomes too short to perform a photoreaction. This is understood in terms of the solvation in the excited state, as follows In the ground state, the copper(I) complex takes a tetrahedral (Td) or pseudo-Td structure because of its d10 electron configuration [45]. In the MLCT excited state, however, the copper center becomes similar to copper(II), which takes a d9 electron configuration. 

In octahedral symmetry, the copper(ll) ion has a electronic ground state due to the d electron configuration with the unpaired electron in an Cg a anti-bonding orbital. An exact octahedral geometry of six-coordinate copper(II) complexes is never realized due to a strong Jahn-Teller effect. The symmetry of the Jahn-Teller active vibration is eg, the non-totally symmetric part of the symmetric square [Eg Eg]. For a Cu(Il)Lg complex, the two components of the degenerate eg vibration are shown in Fig. 1 a [2]. 

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