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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper I covers inorganic chemistry.

UPSC Combined Geo-Scientist, Mains · 2019 · Mains Paper I

Q4(a). Inner- and outer-orbital complexes

Question

What are inner sphere and outer sphere complexes in the framework of Valence Bond Theory? Why [CoF₆]³⁻ is labile while [Co(NH₃)₆]³⁺ is stable?

Answer in brief

The intended VBT distinction is inner-orbital d²sp³ versus outer-orbital sp³d² bonding. High-spin Co(III) fluoride is more substitution-labile than low-spin hexaamminecobalt(III).

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CoversInner-outer-orbital complexesValence-bond treatment

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