Chapter 3, Problem 3.45E

(a)

Interpretation Introduction

Interpretation:

Percentage of vacant space for pure element that crystallizes in primitive cubic lattice has to be determined.

Concept Introduction:

Unit cell represents lattice structure if it stacked together repeatedly with no gaps and rotations. This can also produce whole crystals by stacking method. Basic type of unit cells is as follows:

1. Simple cubic (SC).

2. Body centered cubic (BCC).

3. Face centered cubic (FCC).

Packing efficiency in different unit cells is defined as percentage of space in unit cells occupied by constituent particles. Packing efficiency value for simple cubic, BCC, and FCC lattice is $52.4\text{ \%}$, $68\text{ \%}$, and $74\text{ \%}$ respectively.

(b)

Interpretation Introduction

Interpretation:

Percentage of vacant space present in FCC and primitive cubic lattice unit cell has to be compared.

Concept Introduction:

Refer to part (a).