Calculate the `EAN` of `CO` in `[Co(NH_(3))_(6)]^(3+)`(Atomic number of `Co= 27)` .

Explanation

In `[Co(NH_(3))_(6)]^(3+)=+3`
`Y=No` of electrons gained by coordination `=2 xx 6 =12`
`EAN` of `Co` in `[Co(NH_(3))_(6)]^(3+)=27 - 3 + 12 =36` which
is equal to the atomic number of next higher noble gas which is `(Kr, Z= 36)` Hence Co in `[Co(NH_(3))_(6)]^(3+)` obeys `EAN` rule
Futher examples of complexes whose central atom//ion obeys `EAN` rule are given in Table `7.12` .