Crystal Lattice and Unit Cells

The video tutorial explains crystal structures through unit cells, which are the smallest repeating units forming a crystal lattice. It covers the dimensions and angles of unit cells, introduces the 14 Bravais lattices, and distinguishes between primitive and centered unit cells. The types of centered unit cells, including body-centered, face-centered, and end-centered, are detailed. Finally, the classification of unit cells with further variations is discussed.

What is the smallest portion of a crystal that can be repeated to form a crystal lattice?

• Unit cell

• Crystal structure

• Molecule

• Lattice point

How many possible 3D lattices are there?

• 14

• 10

• 21

• 7

What distinguishes a primitive unit cell from a centered unit cell?

• Presence of particles at the center of two opposite faces

• Presence of particles at the center of each face

• Presence of particles at the center of the body

• Presence of particles only at the corners

In a body-centered unit cell, where is the additional particle located?

• At the center of two opposite faces

• At the corners

• At the center of the body

• At the center of each face

Which type of centered unit cell has a particle at the center of any two opposite faces?

• Primitive unit cell

• Face-centered unit cell

• End-centered unit cell

• Body-centered unit cell