Crystals and Crystalline Structure

What term describes materials like pitch, glass, and many plastics?

What characterizes the internal structure of crystalline materials?

What is shown by the dotted lines joining the centers of spheres in a crystal structure diagram?

How are non-crystalline solids best understood?

What is the term for the geometric figure that illustrates the fundamental grouping of particles in a solid?

How many basic lattices can all crystal structures be analyzed into?

What are the Bravais space lattices?

Which type of unit cell is represented by Figure 1.6 (a)?

What geometric form do crystals take when allowed to grow freely?

Crystalline Structure

Many solid substances, including metals, have a crystalline structure, meaning their basic particles are arranged in a definite 3D pattern of rigid geometrical form, repeated many times.
Crystals take on a distinctive geometric form when allowed to grow freely.
Non-crystalline solids, such as pitch, glass, and some plastic materials, are amorphous (without shape) and can be considered as extremely viscous liquids.

Crystal Structure and Unit Cell

The structure of crystals can be understood by considering their constituent atoms as spherical in shape.
A simple cubic crystal can be built up from eight spherical particles, with the unit cell being the geometric figure that illustrates the fundamental grouping of particles in the solid.
The unit cell is repeated many times to form the space lattice, which characterizes crystalline materials.
The regular, repetitive pattern of particles is a key characteristic of crystalline materials.

Bravais Space Lattices

All crystal structures can be analyzed into fourteen basic lattices, known as the Bravais space lattices.
The Bravais space lattices can be classified into two types: P-type and C-type.
P-type lattices are primitive and shown in Figure 1.6 (a).
C-type lattices are centred on the "ab" face and shown in Figure 1.6 (b).

This quiz is about the structure and properties of crystals, including their geometric forms and arrangements of particles, and how they differ from amorphous solids.