Chapter 16, Problem 62E

Interpretation Introduction

Interpretation : Formula of the nickel arsenide unit cell should be identified.

Concept Introduction :

Hexagonal close packing and cubic close packing are the two major types of close packing of the spheres of a crystal structure.

Face centered cubic close packing (FCC) and body centered cubic close packing (BCC) are the two types of cubic close packing.

There are $8$ corners of cubic unit cell which are occupied by single atom and shared by $8$ unit cells. Also, the $12$ edges are having $12$ atoms and shared by $4$ unit cells. The center of the cube is occupied by one atom. Atom in center cubic unit cell is not shared.