In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion `(Ca^(2+))` and fluoride ion `(F^-)` are

Options

A. 4 and 2
B. 6 and 6
C. 8 and 4
D. 4 and 8

Answer

C

Explanation

In fluorite structure, `Ca^(2+)` ions are in the facecentred cubic arrangement. Each `Ca^(2+)` is connected to `4 F^(-)` ions below it and to another set of `4 F^-` ions above it i.e. `Ca^(2+)` has a coordination number of 8 and each `F^(-)` ion has a coordination number 4.