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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 · 2018 · Mains Paper I

Q4(c). CFSE and pairing

Question

Calculate the crystal field stabilization energy value of the complex [Cr(NH₃)₆]²⁺. The crystal field splitting energy and pairing energy are found to be 150 kJ mol⁻¹ and 120 kJ mol⁻¹ respectively.

Answer in brief

The supplied values favour low-spin d⁴, t_(2g)⁴. Its orbital CFSE is -240 kJ mol⁻¹; including the extra pair gives -120 kJ mol⁻¹.

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CoversCFSEpairingOctahedral ligand fields

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