Q: Percentages of free space in cubic close packed structure and in body centered packed structure are respectively

Explanation:

Cubic Close Packed (CCP) & Body-centered Cubic (BCC) Free Space

In crystal structures, the packing efficiency refers to the percentage of space occupied by the atoms, while the remaining percentage represents the free space or voids.

For the cubic close packed (CCP) structure, also known as the face-centered cubic (FCC) structure, the packing efficiency is 74%. This means that 26% of the space is unoccupied or free. The CCP structure arranges atoms in a way that minimizes the free space, making it one of the most efficient packing methods.

On the other hand, the body centered packed (BCP) structure, commonly referred to as the body-centered cubic (BCC) structure, has a packing efficiency of approximately 68%. Consequently, 32% of the space in the BCP structure is free. The BCP arrangement is less efficient in terms of packing compared to CCP because there is more void space between the atoms.

Therefore, the percentages of free space in CCP and BCP structures are 26% and 32% respectively.