Chapter 20.5, Problem 20.7P

Interpretation Introduction

Interpretation:

The oxidation state of iron in the given complex has to be calculated.

Concept Introduction:

Oxidation number calculation rules:

• For a free element the oxidation number is always $\text{0}$.
• For a monatomic ion the oxidation number equals to the charge of the ion.
• The oxidation number of hydrogen $\left(\text{H}\right)$ is $\text{+1}$, but it gets $\text{-1}$ oxidation when combined with less electronegative elements.
• In compounds, the oxidation number of oxygen $\left(\text{O}\right)$ is usually $\text{-2}$, but its oxidation number is -1 in peroxides.
• For Group 1 elements, the oxidation number in a compound is $\text{+1}$.
• For Group 2 elements, the oxidation number in a compound is $\text{+}\text{2}$.
• For Group 17 elements, the oxidation number in a binary compound is $\text{-}\text{1}$.
• For a neutral compound the sum of the oxidation numbers of all of the atoms is $\text{0}$.
• In a polyatomic ion, the sum of the oxidation numbers is equal to the charge of the ion.