Question

Which of following coordinate complexes is an exception to $EAN$ rule ?
(Given At. No. Pt = 78, Fe = 26, Zn = 30, Cu = 29)

• A. $[Pt(N{H}_3{)}_6{]}^{4+}$
• B. $[Fe(C{N}_3{)}_6{]}^{4-}$
• C. $[Zn(N{H}_3{)}_4{]}^{2+}$
• D. $[Cu(N{H}_3{)}_4{]}^{2+}$

Answer 1

Answer: (D)

${\left[Cu{\left(N{H}_3\right)}_4\right]}^{2+}$ is an exception to EAN rule.
$EAN=Z-X+Y$
$EAN=29-2+8=35$
The atomic number of nearest noble gas $(Kr)$ is $36$ .
Note:
${\left[Pt{\left(N{H}_3\right)}_6\right]}^{4+}$
$EAN=78-4+12=86$
The atomic number of nearest noble gas $(Rn)$ is $86$ .
${\left[Fe(CN{)}_6\right]}^{4-}$
$EAN=26-2+12=36$
The atomic number of nearest noble gas $(Kr)$ is $36$ .
${\left[Zn{\left(N{H}_3\right)}_4\right]}^{2+}$
$EAN=30-2+8=36$
The atomic number of nearest noble gas $(Kr)$ is $36.$