Question

The radius of the Na⁺  is 95 pm and that of Cl^– ion is 181 pm. Predict the coordination number of Na⁺.

(A) 4

(B) 6

(C) 8

(D) Unpredictable

Answer 1

Correct answer is: (B) 6

radius ratio = \(\cfrac{r^+}{r^-}\)=\(\cfrac{95}{181}\)= 0.52

Since the radius ratio is in between 0.414 to 0.732,

the coordination number of cation is 6.