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QJEEAdv18Chf247: JEE Advanced 2018 Chemistry - Class 12 JEEAdv18Chf247 Solution: The correct statement(s) regarding the binary transition metal…

The correct statement(s) regarding the binary transition metal carbonyl compounds is(are) (Atomic numbers : Fe=26,Ni=28Fe = 26,Ni = 28 )

Multiple Choice Options

  • A Total number of valence shell electrons at metal center in Fe(CO)5  Fe{\left( {CO} \right)_5}\,\, or Ni(CO)4Ni{\left( {CO} \right)_4} is 1616
  • B These are predominantly low spin in nature
  • C Metal-carbon bond strengthens when the oxidation state of the metal is lowered.
  • D The carbonyl C−OC-O bond weakens when the oxidation state of the metal is increased

Step-by-Step Verified Solution

(A) [(Fe(CO5)] & [Ni(CO)4 complexes have 18-electrons in their valence shell.

(B) Due to strong ligand field, carbonyl complexes are predominantly low spin complexes.

(C) As electron density increases on metals (with lowering oxidation state on metals), the extent of synergic bonding increases. Hence M-C bond strength increases.

(D) While positive charge on metals increases and the extent of synergic bond decreases and hence C-O bond becomes stronger.

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