Question

How do you find oxidation numbers in complex compounds?

Answer 1

We know that the transition metals typically form several oxidation states and therefore have several oxidation numbers. Also the oxidation number of an atom is the charge that would exist on the atom if the bonding were completely ionic. In simple ions, the oxidation number of the atom is the charge on the ion. In a molecule or compound, the oxidation number is the sum of the oxidation numbers of its constituent atoms.

Complete answer:
Considering a complex compound $[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}$ . We know that the chloride counterparts with the ions each have $-1$ charge. Thus we can separate the charges $[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}+3\times C{{l}^{-}}$ while maintaining efficiency.
We have to preserve the charge here: we should start with a neutral complex, and it's still neutral as required. Then we should dismember the metal complex we have to recognize the ammine ligand as a neutral entity; $C{{o}_{3}}^{+}+6AN{{H}_{3}}$ the same as I would for a phosphine $P{{R}_{3}}$ or carbonyl $C\equiv O$ ligand.
Splitting this up we get and then we have a Centre.

Note: Important things to keep in consideration that the atoms with d-shell electrons can have several different oxidation numbers.
-In complex ions or molecules, the oxidation numbers of these atoms can be calculated if we assume that the oxidation numbers of the other atoms in the species are fixed.
-Similarly the oxidation number of an atom is the charge that would exist on the atom if the bonding were completely ionic.
-In simple ions, the oxidation number of the atom is the charge on the ion.
-In a molecule or compound, the oxidation number is the sum of the oxidation numbers of its constituent atoms.
-Atoms with d-shell electrons can have several different oxidation numbers.
-In complex ions or molecules, the oxidation numbers of these atoms can be calculated if we assume -that the oxidation numbers of the other atoms in the species are fixed.
-The oxidation numbers of metals with more than one oxidation state are represented by Roman numerals.