Question

The three dimensional graph of lattice points which sets the pattern for the whole lattice is called :

• A. Lattice point
• B. Space lattice
• C. Crystal lattice
• D. Unit cell

Answer 1

The correct option is D Unit cell

Unit cell is the smallest portion of a crystal lattice which, when repeated in different directions, generates
the entire lattice.


A unit cell is characterised by:

1. Its dimensions along the three edges, a, b and c. These
   edges may or may not be mutually perpendicular.
2. Angles between the edges, $\alpha$ (between b and c), $\beta$ (between a and c) and $\gamma$ (between a and b). Thus, a unit cell is characterised by six parameters : $a,b,c,\alpha ,\beta and\gamma$.