What is d orbital occupation in the given compound.
${{K}_{3}}[Co{{({{C}_{2}}{{O}_{4}})}_{3}}]$

Hint: Coordination number is the number of atoms, ions, or molecules that a central atom or ion holds as its nearest neighbours in a complex or coordination compound or in a crystal.

Complete answer:
- Coordination numbers are generally between two and nine. The number of bonds depends on the size, charge, and electron configuration of the metal ion and the ligands.
- Typically, the chemistry of complexes is dominated by interactions between s and p molecular orbitals of the ligands and the d orbitals of the metal ions.
- For molecules and polyatomic ions, the coordination number of an atom is determined by simply counting the other atoms to which it is bonded by either single or multiple bonds.
- An orbital is defined as a region in an atom where there is a high probability of finding an electron.
- The d orbital is a clover shaped due to the electrons being pushed out four times during the rotation when an opposite spin proton aligns gluons with three spin-aligned protons.
- In the question, the central metal ion is Cobalt (Co)
Co has coordination number 6
- The oxidation state can be shown as
$\begin{align}
& x-6=-3 \\
& x=+3 \\
\end{align}$
So, the oxidation state is +3
- Since, oxalate is a strong field ligand, pairing will occur. This will keep the $eg$ orbital empty. Therefore, the complex, ${{K}_{3}}[Co{{({{C}_{2}}{{O}_{4}})}_{3}}]$ is diamagnetic.

- The d orbital occupation will be \[t_{2g}^{6}e_{g}^{0}\]

Note: The d orbitals give transition metals their special properties. In transition metal ions the outermost d orbitals are incompletely filled with electrons so they can easily give and take electrons.