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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 · 2021 · Paper I

Q5(d). Geometrical isomers and stereoisomers of M(AB)b₂c₂

Question

How many geometrical isomers and stereoisomers are possible in the coordination compounds of the type M(AB)b₂c₂ (AB — bidentate ligand)?

Answer in brief

For octahedral M(AB)b₂c₂ there are 4 geometrical isomers and 6 stereoisomers: two are optically inactive and two are chiral, each a pair of enantiomers.

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Topic notes: Werner theory, isomerism, IUPAC names and valence bond theory of complexes, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversgeometrical isomerismoptical isomerismoctahedral complexesunsymmetrical bidentate ligandstereoisomers

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