Most Important Selected Qs for JEE AdvancedChemistrySolid State
For the ionic compound A ₃ ~B , which of the following statements are correct, if radii of A ⁻ and B ³⁺ ion are respectively 5 x and 2 x and the lattice points have hcp arrangement?
Options
- A5 6 th of tetrahedral voids are vacant
- B1 3 rd of total voids are vacant in compound
- CThe coordination number of B ³⁺ is 4
- DThe coordination number of A ⁻ is 8
Correct answer
C. The coordination number of B ³⁺ is 4
Step-by-step solution
Radius ratio ( r ⁺ r ⁻ )= 2 x 5 x =0.4 , coordination number of B ³⁺ 4 Formula of the compound is A₃ B , i.e., 1 6 th of tetrahedral sites are occupied by B ³⁺ and so vacant tetrahedral sites are 5 6 th.