Question

What is the coordination number of sodium in $Na_2O$ ?

• A. 6
• B. 4
• C. 8
• D. 2

Answer 1

Answer: (B)

4

Answer 2

In $Na_2O , O^{2-}$ ions adopts $f.c.c.$ lattice in which $Na^+$ ions are present at all tetrahedral sites. $\therefore$ Co-ordination number of $Na^+$ ion $= 4$