Question

What is the coordination number of sodium in sodium oxide (Na₂O)? 

(a) 6 

(b) 4 

(c) 8 

(d) 2

Answer 1

Correct Answer is: (b) 4 

The coordination number of Na in Na₂O is 4. Na⁺ ion is surrounded by four oxide ions and O₂^- ion is surrounded by eight Na⁺ ions hence the coordination number of Na in Na₂O is 4.