Which of the following has minimum C-O bond order? a) (Mn(CO)6)+ b) (N...
Minimum C-O bond order among (Mn(CO)6), (Ni(CO)4), (Fe(CO)4)2-, and (Co(CO)4)-
Bond order is defined as the half-difference between the number of electrons in bonding and anti-bonding orbitals. The C-O bond order in the given complexes can be calculated as follows:
a) (Mn(CO)6)
Manganese has 25 electrons, and each CO ligand donates two electrons to the metal center. Therefore, the total number of electrons in the complex is 37. The Mn atom has d5 configuration, and all the electrons reside in the bonding molecular orbitals. Hence, the bond order is calculated as follows:
Bond order = (number of bonding electrons - number of anti-bonding electrons)/2
= (30 - 0)/2
= 15
b) (Ni(CO)4)
Nickel has 28 electrons, and each CO ligand donates two electrons to the metal center. Therefore, the total number of electrons in the complex is 36. The Ni atom has d8 configuration, and the last two electrons are accommodated in the anti-bonding orbitals. Hence, the bond order is calculated as follows:
Bond order = (number of bonding electrons - number of anti-bonding electrons)/2
= (16 - 2)/2
= 7
c) (Fe(CO)4)2-
Iron has 26 electrons, and each CO ligand donates two electrons to the metal center. Therefore, the total number of electrons in the complex is 34. The Fe atom has d6 configuration, and the last two electrons are accommodated in the anti-bonding orbitals. Hence, the bond order is calculated as follows:
Bond order = (number of bonding electrons - number of anti-bonding electrons)/2
= (20 - 2)/2
= 9
d) (Co(CO)4)-
Cobalt has 27 electrons, and each CO ligand donates two electrons to the metal center. Therefore, the total number of electrons in the complex is 35. The Co atom has d7 configuration, and one electron resides in the anti-bonding molecular orbital. Hence, the bond order is calculated as follows:
Bond order = (number of bonding electrons - number of anti-bonding electrons)/2
= (18 - 1)/2
= 8.5
Therefore, the complex with the minimum C-O bond order is (Co(CO)4)- with a bond order of 8.5.
Which of the following has minimum C-O bond order? a) (Mn(CO)6)+ b) (N...
C)..bcs of more - ve charge on carbonyl complex.. there will be more back bonding with metal electrons, reducing C-O bond order..
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