Crystalline and Amorphous Solids: Explanation, Differences, Examples, etc

Think of a diamond and some cotton candy. Do you think these substances are alike? They are different in every aspect, and yet they are both solids. What differentiates these is the structure and arrangement of their particles. Let us learn about the two types of solids, crystalline Solids and Amorphous Solids.

Crystalline Solids

These are the most common type of solids. Their characteristics are what we associate solids with. They are firm, hold a definite and fixed shape, are rigid and incompressible. They generally have geometric shapes and flat faces. And examples include diamonds, metals, salts etc.

To understand crystals we must understand their structure. The arrangement of particles in a crystalline solid is in a very orderly fashion. These articles are arranged in a repeating pattern of a three-dimensional network. This network is known as a Crystal lattice and the smallest unit of a crystal is a Unit Cell. If you see the X-ray of a crystal this distinct arrangement of the unit cells will be clearly visible.

Learn more about Magnetic Properties of Solid here in detail.

The spaces between the atoms are very less due to high intermolecular forces. This results in crystals having high melting and boiling points. The intermolecular force is also uniform throughout the structure. Crystals have a long-range order, which means the arrangement of atoms is repeated over a great distance.

Crystalline and Amorphous Solids

Amorphous Solids

Amorphous solids are rigid structures but they lack a well-defined shape. They do not have a geometric shape. So they are non-crystalline. This is why they do not have edges like crystals do. The most common example of an amorphous solid is Glass. Gels, plastics, various polymers, wax, thin films are also good examples of amorphous solids.

This variation in characteristics of solids occurs due to the arrangement of their molecules. Here the particles of matter do not form the three-dimensional lattice structure that we see in solids. Some naturally occurring amorphous solids have impurities that prevent such a structure from forming. So they have a short order arrangement of molecules.

Amorphous solids break into uneven pieces with irregular edges. And they do not have any distinct arrangement or shape of molecules. so they cannot be identified by their structure as crystals.

Learn abut Tetrahedral voids and Octahedral voids here.

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Difference Between Crystalline and Amorphous Solids

Crystals have an orderly arrangement of their constituent particles. In comparison, amorphous solids have no such arrangement. Their particles are randomly organised.
Crystals have a specific geometric shape with definite edges. Amorphous solids have no geometry in their shapes
Crystalline solids have a sharp melting point on which they will definitely melt. An amorphous solid will have a range of temperature over which it will melt, but no definite temperature as such
Crystals have a long order arrangement of their particles. This means the particles will show the same arrangement indefinitely. Amorphous solids have a short order arrangement. Their particles show a lot of variety in their arrangement.
Crystalline solids cleavage (break) along particular points and directions. Amorphous solids cleavage into uneven parts with ragged edges.
Crystals are also known as True Solids, whereas another name for Amorphous Solids is Super-Cooled Liquids.

Learn more about Electrical Properties of Solid here in detail.

Solved Examples for You

Question: Assertion- Initially the term pseudo solid was given for solids, which were easily distorted by bending and compression forces. They even tend to flow slowly under its own mass and lose shape.

Reason- These characteristics are shown by pseudo solids as in pitch, glass and thus, the name pseudo solid was replaced by supercooled liquids.

Both Assertion and Reason are Correct and the Reason is the correct explanation for Assertion
Both Assertion and Reason are Correct but the Reason is not the correct explanation for Assertion
Assertion is correct but Reason is incorrect
Both Assertion and Reason are incorrect

Solution: Option B. Both Assertion and Reason are Correct but the Reason is not the correct explanation for the Assertion. Initially, the term pseudo solid was given for amorphous solids, which were easily distorted by bending and compression forces. They even tend to flow slowly under its own mass and lose shape.

The intermolecular forces present in such materials are stronger than those present in the liquids but weaker than those present in solids. They are not solids in the real sense. The regular arrangement of constituent particles is present only up to short distance in these solids. These characteristics are shown by pseudo solids as in pitch, glass and thus, the name pseudo solid was replaced by supercooled liquids.

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