Answer: Fe4[Fe(CN) 6 ]3 (mixed valence Fe 2+ /Fe 3+ complex with CN- bridges).
- A Fe4[Fe(CN)<sub>6</sub>]3 (mixed valence Fe<sup>2+</sup>/Fe<sup>3+</sup> complex with CN- bridges)
- B A simple aqueous CuSO<sub>4</sub> solution with little iron present according to conventional understanding
- C Plain FeCl<sub>3</sub> dissolved in water with little cyanide bridges
- D K3[Fe(CN)<sub>6</sub>], the separate potassium ferricyanide salt in routine practice
Correct answer: A. Fe4[Fe(CN)<sub>6</sub>]3 (mixed valence Fe<sup>2+</sup>/Fe<sup>3+</sup> complex with CN- bridges)
Explanation: Prussian blue is iron(III) hexacyanoferrate(II), a coordination network used as a blue pigment and in detoxification of heavy metals.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.