The following diagram shows crystal field splitting pattern for a complex. Which one of the complexes given below should best match the given diagram?

• A. [Ag(NH₃)₂]⁺
• B. [Cu(ox)₂]^2–
• C. [Cr(en)₃]³⁺
• D. [Fe(CO)₅]

Answer: (C)

Verified step by step guidance

1. Identify the crystal field splitting pattern shown in the diagram. The diagram shows a splitting pattern with two levels: a lower set of three orbitals and an upper set of two orbitals, which is characteristic of an octahedral complex.
2. Understand the concept of crystal field splitting. In an octahedral complex, the d-orbitals split into two sets: the lower energy t2g set (three orbitals) and the higher energy eg set (two orbitals).
3. Analyze the given complexes to determine which one is likely to exhibit the octahedral splitting pattern. Consider the geometry and ligands of each complex.
4. Evaluate the geometry of each complex: [Ag(NH3)2]+ is linear, [Cu(ox)2]2– is square planar, [Cr(en)3]3+ is octahedral, and [Fe(CO)5] is trigonal bipyramidal.
5. Conclude that [Cr(en)3]3+ is the complex that best matches the octahedral crystal field splitting pattern shown in the diagram, as it is the only complex with an octahedral geometry.