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UPSC Civil Services (Mains)

Chemistry optional

  • 2 papers
  • 250 marks each
  • 3 h per paper
  • 5 of 8 questions, Q1 and Q5 compulsory

Paper I covers physical and inorganic chemistry.

UPSC Civil Services (Mains), Chemistry optional · 2022 · Paper I

Q5(d). [Ni(CO)₄] and [Ni(CN)₄]⁴⁻: names, structures and shapes

Question

Write IUPAC nomenclature of [Ni(CO)₄] and [Ni(CN)₄]⁴⁻. Give structure and draw their shapes with explanation.

Answer in brief

[Ni(CO)₄] is tetracarbonylnickel(0); [Ni(CN)₄]⁴⁻ is the tetracyanidonickelate(0) ion; both contain Ni(0), 3d¹⁰, with sp³ hybrid orbitals: tetrahedral, diamagnetic, 18-electron complexes.

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Read the whole 2022 solution2022 question paper

Topic notes: metal carbonyls, nitrosyls, the 18-electron and EAN rules, metal–metal bonds and clusters, with every Civil Services, IFoS and Geo-Scientist PYQ →

CoverstetracarbonylnickelIUPAC nomenclaturesp3 hybridisation18-electron ruleπ back-bondingMond process

All parts of Question 5