How to find out the oxidation number?

[tonyhu]

Like the Fe in porphyrins especially

[Jessica Tejero 3L]

The oxidation number of an atom is zero in a neutral substance that contains atoms of only one element. Atoms in O2, O3, P4, S8, and aluminum metal all have an oxidation number of 0. The oxidation number of simple ions is equal to the charge on the ion. The oxidation number of sodium in the Na+ ion is +1 and the oxidation number of chlorine in the Cl- ion is -1.

[chrisleung-2J]

Oxidation numbers can usually be determined by considering the oxidation number of known atoms to find those that are unknown. For example, O typically has an oxidation number of -2 and H typically has an oxidation number of +1, so in HNO3, which is neutral overall, we can use algebra to determine that the oxidation number of N with the equation 1 + x + 3(-2) = 0 meaning that x= +5.

[ranqiao1e]

The oxidation number of the central atom in a coordination compound depends on the oxidation number of the ligand.