Write the chemical formula for the complex Iron (III) hexacyanoferrate (II) is

CONCEPT:

Coordination Compounds and Complex Ions

• Coordination compounds consist of a central metal atom or ion bonded to surrounding ligands (molecules or ions).
• The formula of a coordination compound is written as [Metal(Ligand)_n].
• The oxidation state of the metal ion is indicated in Roman numerals in parentheses.

EXPLANATION:

• In the given complex, Iron (III) hexacyanoferrate (II):
  • Iron (III) indicates that the central iron ion has an oxidation state of +3.
  • Hexacyanoferrate (II) indicates that the hexacyanoferrate ion has an iron ion with an oxidation state of +2 and is coordinated with six cyanide (CN^-) ligands.
• The hexacyanoferrate (II) ion is [Fe(CN)₆]^4-, because each CN has a -1 charge and there are 6 of them, making the total charge of the ion -4.
• To balance the charges, three Fe³⁺ ions are needed to neutralize the charge of four [Fe(CN)₆]^4- ions.

Therefore, the chemical formula for Iron (III) hexacyanoferrate (II) is Fe₄[Fe(CN)₆]₃.