Question

The ratio of r+:r is 0.42 the coordinations number of cation is

Answer 1

Answer: The coordination number is 6.

Explanation:

Radius ratio = $\frac{\text{Radius of the cation}}{\text{Radius of the anion}}$

1) 0.155 to 0.225 for 3 coordination number

2) 0.225 to 0.414 for 4 coordination number

3) 0.414 to 0.732 for 6 coordination number

4) 0.732 to 1 for 8 coordination number

Given radius ratio of the crystal lattice = $\frac{r_+}{r_-}=0.42 or 0.420$

The radius ratio of the given crystal lattice is 0.420 which is lying in between the range of 0.414 to 0.732 radius ratio for coordination number 6. The coordination number is 6.