Answer: [CoF6]3- (F- is weak field, uses 4d orbitals, sp3d2, high spin).
- A [CoF6]3- (F- is weak field, uses 4d orbitals, sp3d2, high spin)
- B [Co(CN)6]3-, an inner orbital low-spin complex using 3d orbitals
- C [Co(NH3)6]3-, an inner orbital low-spin complex using 3d orbitals
- D [Fe(CO)5], a zero-valent carbonyl complex with trigonal bipyramidal geometry
Correct answer: A. [CoF6]3- (F- is weak field, uses 4d orbitals, sp3d2, high spin)
Explanation: [CoF6]3-: F- is weak field; outer orbital hybridisation uses 4s, 4p, 4d (not 3d); it is high spin with 4 unpaired electrons.
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.