What is the co-ordination number of sodium in `Na_(2)O` ?

Options

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

Answer

B

Explanation

`Na_(2)O` has antifluorite structure `O^(2-)` ions constitute ccp lattice while `Na^(+)` ions occupy the tetrahedral voids. Each `O^(2-)` ion is in contact with 8 `Na^(+)` ions and each `Na^(+)` ion is in contact with `4O^(2-)` ions. The C.N. of sodium in `Na_(2)O=4`