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.
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, salt 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.
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.
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.
Study Tetrahedral voids and Octahedral voids here .
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.
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.
- 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 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.
Electrical Properties of Solids
General Introduction to the Solid State
Density of a Cubic Crystal
Close Packing in Crystals
Number of Particles in Unit Cells
Space lattice or Crystal lattice and Unit Cell
Magnetic Properties of Solids
Imperfections or Defects in a Solid
Tetrahedral and Octahedral Voids
Crystalline and Amorphous Solids
Radius Ratio Rule
How do crystalline solids differ from amorphous solids?
, B.Tech In Metallurgy and Materials Engineering, Veer Surendra Sai University of Technology, Burla (2019)
Crystalline Solids :-
- The constituent particles are arranged in a regular order.
- It exhibit both short range and long range order.
- It has sharp melting points.
- It shows definite heat of fusion.
- It undergoes a clean cleavage.
- It shows anisotropy in physical property measurements.
- Crystalline solids are true solids.
- e.g. sodium chloride
Amorphous Solids :-
- The constituent particles shows disordered arrangements.
- It exhibits short range orders.
- It melts over a range of temperatures.
- These solids do not have any definite heat of fusion.
- It cut regularly.
- These solids are isotropic.
- Amorphous solids are pseudosolids or supercooled liquids.
- e.g. Quartz glass, Rubber , Plastics
, BSc in Materials Science and HBA in Business Administration
Here is a link describing the different Unit Cells in crystals.
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, B. E. Electrical and Electronics Engineering, Andhra University College of Engineering (2020)
1. There is only a short range order in amorphous solids
2. Amorphous solids do not have a sharp melting point; they are softened in a range of temperature.
3. Amorphous solids undergo irregular or conchoidal breakage.
4. Amorphous solids are isotrophic-the properties will be independent of the direction in which they are measured.
5. Less rigid.
Examples of Amorphous solids: Fibre glass, Cellophane, Teflon, Polyurethane, Naphthalene, Polyvinyl chloride.
1. There is a long range order in crystals.
2. Melt at a sharp temperature.
3. Crystalline solids can be cleaved along definite planes.
4. Crystalline solids, in general are anisotrophic (It means that, their properties such as electrical conductivity, refractive index, thermal expansion etc. will be different directions).
5. More rigid.
Examples of Crystalline solids: Copper, Potassium nitrate, Benzoic acid.
, B.sc Chemistry & Science, Jj College of Arts and Science,pudukkottai (2019)
- Crystalline solids have definite and added arrangement of constituent extended over a long distance and is defined as long range order.
- They possesses a Sharp melting point.
- Amorphous solids like glass ,rubber, etc although possessing many characteristics of crystalline solids as definite shape, rigidity, and hardness, but are devoid of regular internal structure and melts gradually over a range of temperature.
, Master in Chemistry
By definition, a crystal is a homogenous, anisotropic and translation-periodic solid.
homogenous: The amount of atoms is proportional with the volume of the solid.
anisotropic: This refers to the direction-dependancy of physical properties: e.g. light-refraction, diffraction, rigidity ….
translation-periodicity: There is the smallest unit of a crystal; it is called the crystals primitive cell/elementary cell! Three-dimensional periodic arrangement of these cells result in the formation of a crystal. So a long-range order exists in a crystal! Think of the unit to be a single brick and the crystal consists of EXACTLY the same bricks!
There are two-dimensional crystals as well, like in an LCD! And non-classic crystals are a special case!
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, Myself & my wife practiced Bhagavadgita for more than 25 yrs
Hari om, you are asking a question as to: “What is the difference between the crystalline and amorphous solids?”.
Browse the website given below for your help and advice:
Amprphous Solids-Crystalline Solids