Question

What is the coordination number of sodium in $N{a}_{2}O$ ?

• A. 6
• B. 4
• C. 8
• D. 2

Answer 1

Answer: (B)

In $N{a}_{2}O,O^{2-}$ ions adopts $f.c.c.$ lattice in which
$N{a}^{+}$ ions are present at all tetrahedral sites.
$\therefore$ Co-ordination number of $N{a}^{+}$ ion $=4$