Question

EAN of Na3[Cr(C2O4) 3]

Answer 1

Answer:

The EAN of Cr in the given complex is 33.

Explanation:

Formula to find EAN is:

EAN=(Atomic number of central metal atom-Oxidation state of central metal atom)+(Coordination number × 2).

Here,

Atomic no. of Cr=24

Oxidation state of Cr=+3

Coordination no. of (C2O4)3=6

By Putting the values in this formula:

EAN of Cr =(24-3)+6×2

=21+12

EAN of Cr = 33

Hence, EAN of Cr in the given complex is 33

Answer 2

EAN of  $\[N{{a}_{3}}\left[ Cr{{\left( {{C}_{2}}{{O}_{4}} \right)}_{3}} \right]\]$ is  $33$

Explanation:

• E.A.N stands for Effective atomic number.

• This rule was proposed by Sidwick.

• We get E.A.N by  adding the number of electrons on the metal and the electrons donated by the ligands.

• The given complex can be written as  $\[{{\left[ Cr{{\left( {{C}_{2}}{{O}_{4}} \right)}_{3}} \right]}^{3-}}\]$ if the sodium ion present in the complex is ionized.
• Chromium is a d-block element and the total numer of electrons present in it is twenty four.
• So,E.A.N = atomic number of central metal atom $-$ oxidation number of central metal atom $+2$ (coordination number of central metal atom)

• Hence, $E.A.N=24-3+2(6)=24-3+12=33$.