Among the following statements, identify the correct ones for complexes of lanthanide (III) ion.
\[ \begin{array}{l} \text{(A) Metal-ligand bond is significantly ionic.} \\ \text{(B) Complexes rarely show isomerism.} \\ \text{(C) The coordination number is not more than 8.} \\ \text{(D) The magnetic moments are not accounted even approximately by spin only value for majority of lanthanides.} \end{array} \]
(a)A, B and D only
(b)A, B and C only
(c)B and C only
(d)A and D only
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
Ln(III)–ligand bonding is mainly ionic, and isomers are rare. Coordination numbers reach 12, so (C) is false. For most Ln(III) ions the spin-only formula fails because spin–orbit coupling gives J-based moments. A, B and D (a).