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GATE 2022 CY – Question 19

Inorganic Chemistry · Transition Metals: Coordination chemistry – structure and isomerism, theories of bonding (VBT, CFT, and MOT). Metal-metal multiple bonds. Energy level diagrams in various crystal fields, CFSE, applications of CFT, Jahn-Teller distortion. Electronic spectra of transition metal complexes: spectroscopic term symbols, selection rules, Orgel and Tanabe-Sugano diagrams, nephelauxetic effect and Racah parameter, charge-transfer spectra. Magnetic properties of transition metal complexes. Ray-Dutt and Bailar twists, Reaction mechanisms: kinetic and thermodynamic stability, associative, dissociative substitution and redox reactions. · 1 mark · Multiple choice

The numbers of metal–metal bonds with $\sigma$, $\pi$, and $\delta$ character in $[Mo_2(CH_3CO_2)_4]$, respectively, are ______.

  1. 1, 2, 1
  2. 1, 2, 0
  3. 1, 1, 0
  4. 1, 1, 1

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Correct answer: (A) 1, 2, 1

Explanation

Four acetates require Mo(II) at each metal, giving d4+d4=eight metal-based electrons. They fill σ²π⁴δ² with no occupied antibonding partners. The quadruple bond therefore comprises **one σ, two π, one δ, A**.