If in a closest packed arrangement `r` is the radius of the sphere respresenting the tetrahedral void and `R` is the radius of the spheres in closest packed arrangement then

Options

A. `r//R=0.732`
B. `r//R=0.155`
C. `r//R=0.225`
D. `r//R=0.414`

Answer

3

Explanation

For tetrahedral coordination the limiting radius ratio is given as
`0.225 ler//R le0.414`
The maximum size of the sphere occupying the void is `0.414R` if the sphere to occupy the tetrahedral voids have size larger than this the arrangement will not longer be closet packed.