What are the charge and coordination number of the central metal ion(s) in each compound of Problem 23_55?

A coordination complex consists of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents.

The coordination number is the number of ligands directly attached to central metal ion in a coordination compound. These ligands can be ions, atoms or molecules. The most common coordination number is 0, but it is also not rare to see 2 and 4 as coordination numbers.

$\left[Ni{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]C{l}_2$ - There are six ligands (H₂O) bonded with central metal ion ( (Ni) so the coordination number of central metal ion is 6 . H₂O is neutral ligand and Cl is counter ion with -l charge, so the charge of the central metal ion will be +2

$\left[\mathrm{Cr}{\left(\mathrm{en}\right)}_3\right]{\left({\mathrm{ClO}}_4\right)}_3$ - There are three bidentate ligands (en) bonded with central metal ion (Cr), so the coordination number of central metal ion is 6. en is neutral ligand and CIO₄ is a counter ion with -1 charge, so the charge of the central metal ion will be +3

$K_4\left[\mathrm{Mn}{\left(\mathrm{CN}\right)}_6\right]$- There are six ligands (CN) around central metal ion (Mn), so the coordination number of central metal ion will be 6 . CN has - 1 charge and is a counter ion with charge, so the charge of the central metal ion will be +2