The `Ca^(2+)` and `F^(-)` ions arc located in `CaF_(2)` crystal respectively at face centred cubic lattice points and in

Options

A. tetrahedral voids
B. half of tetrahedral voids
C. octahedral voids
D. half of octahedral voids

Answer

1

Explanation

The `Ca^(2+)` ions from a face centered cubic arrangement .The `Ca^(2+)` ions are too small to touch each other ,so the structure is not close packed. However the structure is releated to a close-packed arrangement since the `Ca^(2+)` ions occupy the same relative positions as for a cubic close -packed structure and the `F^(-)` ions occupy all the tetrahedral voids.