Chapter 9, Problem 57QRT

Interpretation Introduction

Interpretation:

Two dimensional unit cell for each array has to be drawn.  The no. of atom cells present in each unit cell also has to be determined.

Concept Introduction:

Unit cell:

The smallest group of atoms or molecules, whose repetition at regular intervals in $3D$ or $2D$ results into a crystal is called as a unit cell.

A unit cell should be drawn with the corners at the centers of the atoms instead of in the space between the atoms.