Ferrate vs Iron

[Meghan Yi 3H]

How do you know when do use ferrate vs iron when naming a compound?
For example with the compound [Fe(en)2(NO2)2]3+ are you supposed to use ferrate or iron, or is there no difference?

[Kevin_Conrad_2E]

The choice between using "ferrate" or "iron" in the name of an iron-containing coordination compound depends on the oxidation state of the iron and the nature of the compound, whether it's a complex ion or a simple ion. The rules are as follows:

Iron: When naming coordination complexes where iron is the central metal, the name "iron" is used, followed by its oxidation state in Roman numerals in parentheses. This naming is used regardless of whether the iron is in a positive or negative oxidation state.

Ferrate: The term "ferrate" is typically used for compounds where iron is in a high oxidation state (usually +6 or +5) and is part of an anionic complex. Ferrates are often oxoanions of iron, like in potassium ferrate (where iron is in the +6 oxidation state.

For the complex [Fe(en)2(NO2)2]3+, you should use "iron" for naming because it is a cationic complex with iron as the central metal.