Co-ordination number (CN) of barium ion `(Ba^(2+))` in `BaF^(2)` is 8. What is the CN of `F^(-)` ion ?

Explanation

C.N. of barium ion tells us that it is surrounded by eight fluoride ions (charge `8 xx (-1) = -8`). In order to balance out the eight negative charges, we need four barium ion (charge `4 xx (+2) = +8`). Hence, the C.N. of `F^(-)` ions must be 4