Question

The stabilizations of coordination compound due to chelating is called the chelate effect. Which of the following is the most stable complex species?

• A. $\lbrack Fe(CO)_{5}\rbrack$
• B. $\lbrack Fe(CN)_{6}\rbrack^{3 -}$
• C. $\lbrack Fe(C_{2}O_{4})_{3}\rbrack^{3 -}$
• D. $\lbrack Fe(H_{2}O)_{6}\rbrack^{3 +}$

Answer 1

Answer: (C)

$\lbrack Fe(C_{2}O_{4})_{3}\rbrack^{3 -}$

Answer 2

$C_{2}O_{4}^{2 -}$ (oxalate) is didentate ligand and forms chelate complexes which are more stable than similar complexes containing unidentate ligands.