Question

Percentages of free space in cubic close-packed structure and in the body-centered packed structure are respectively ______.

Options

• 30% and 26%

• 26% and 32%

• 32% and 48%

• 48% and 26%

Answer 1

Percentages of free space in cubic close-packed structure and in the body-centered packed structure are respectively 26% and 32%.

Explanation:

The packing fraction is defined as the ratio of the sphere-occupied volume of the unit cell to the total volume of the unit cell. The Packing efficiency values for cpp and bcc are 0.74 and 0.68, respectively. As a result, free space in ccp and bcc is 26% and 32%, respectively.