Roman numeral

[Chisomaga Azu]

How do we calculate the roman numeral that comes after the metal ion?

[Salma_Lara_2k]

The Roman numeral following a metal ion in a coordination compound represents the oxidation state of that metal ion and to determine this number, you need to consider the charges of the ligands surrounding the metal ion. The number will show how many electrons the ion has gained or lost to reach the state shown in the complex.

[morgantolbert]

And sometimes multiple metals can vary in oxidation state so you can add up all the charges of the central metal ion and the charges of the ligand and make sure it equals the overall charge of the compound.