What is the coordination number and the oxidation state of the metal in each of the following complexes ?
`(a) [ZrF_(8)]^(4-) " ," (b)K_(3)[Cr(C_(2)O_(4))_(2)Cl_(2)]`

Explanation

The coordination number of the central atom/ion is determined by the number of sigma bond between the ligands and the central atom/ion i.e. the number of ligands donor atoms to which the metal is directly attached.
The oxidation number of the central atom is defined as the change it would carry if all the ligands are removed along with the electron pairs that are shared with the central atom.
`{:("Complex","Coordination Number","Oxidation State"),((a)[ZrF_(8)]^(4-),8,4),((b)K_(3)[Cr(C_(2)O_(4))_(2)Cl_(2)],6,3):}`