In the metal carbonyls of general formula M C O x (Which follows EAN rule) if M is Ni, Fe and Cr the value of x will be respectively:-
(1) 6, 5, 6
(2) 4, 5, 6
(3) 4, 4, 5
(4) 4, 6, 6
Answers
Answer:
4,5,6
Explanation:
As Ni Fe Cr follows EAN
then,M(CO)x oxidation state of metal is 0
so,36 effective atomic number make 3d element more stable
36=28-0+2(x)
x=4.....Ni
36=26_0+2(x)
x=5....Fe
36=24- 0+2(x)
x=6...Cr
Explanation:
Option (2) is correct.
Generally EAN of central metal atom/ion will be equal to the number of electrons present in the nearest Noble gases.
It can be calculated using the formula
EAN = Z - X + Y
Where as
- Z= atomic number of the metal
- X= number of electrons lost during the formation of the metal ion from its atom
- Y= number of electrons donated by the ligands.
Y = 2 for Carbonyls
The metal carbonyls of general formula M (CO) x
(1) M = Ni(Z = 28) , x = 4 The complex is Ni(CO)₄
[Metal oxidation state (X) = 0 )]
EAN = 28 + 0 + 2 x 4 = 36 is the atomic number of Krypton
(2) M = Fe (Z = 26) , x = 5 The complex is Fe(CO)₅
[Metal oxidation state (X) = 0 ]
EAN = 26 + 0 + 2 x 5 = 36 is the atomic number of Krypton
(3) M = Cr (Z = 24), x = 6 The complex is Cr(CO)₆
[Metal oxidation state (X) = 0 ]
EAN = 24 + 0 + 2 x 6 = 36 is the atomic number of Krypton