Question

How many tetrahedral and octahedral void spaces are three for each sphere in close packing?

Answer 1

This question comes under the branch of chemistry called solid state chemistry.
Here, it is given that cubic closed packed structure (CCP) that is nothing but face centered cubic structure (FCC). There are 1 mole of octahedral voids in 1 mole of compound having CCP structure. This is because, the number of octahedral voids depend upon the number of spheres. If there are N spheres involved in packing then there are N octahedral voids. In CCP, it has 4 atoms in one unit cell therefore we can say that in one mole, total atoms is 4(NA)
where NA means, Avagadro number
Here it is asked that how many octahedral voids are present in 1 mole of a compound having CCP structure. So that number of octahedral void is same as number of spheres. Therefore number of octahedral void is 4NA.
Conclusion : Number of octahedral voids present in 1 mole of a compound having CCP structure is 4NA.
and in the same way tetrahedal void is twice of no of atom present therfore in CCP structure tgere is number of tetrahedal voids is 8NA