crystal

Introduction
Classification
- Basic units of solids
- Long- and short-range order
- Categories of crystals
Structure
- The unit cell
- Structures of metals
- Structures of nonmetallic elements
- Structures of binary crystals
- Alloys
- Crystal defects
- Determination of crystal structures
Types of bonds
- Ionic bonds
- Covalent bonds
- Metallic bonds
- Molecular binding
- Hydrogen bonding
Crystal growth
- Vapour growth
- Growth from solution
- Growth from the melt
- Dendritic growth
Electric properties
- Resistivity
- Conduction through ion hopping
- Conduction electrons
- Electrical insulators
- Conductivity of metals
- Conducting properties of semiconductors
Magnetism
- Explanation of magnetism
- Ferromagnetic materials
- Antiferromagnetic materials
- Ferrimagnetic materials
- The Kondo effect

References & Edit History Quick Facts & Related Topics

Images & Videos

A rough, translucent yellow crystal of elemental sulfur displayed against a solid black background.

A cluster of purple crystals with jagged surfaces sits on a black background, illustrating the result of the crystallization process.

What Are the Seven Basic Crystal Systems?

Diagram showing four types of crystal bonding: ionic bonding with sodium and chlorine ions, covalent bonding with carbon atoms sharing electrons, metallic bonding with iron ions surrounded by free electrons, and molecular bonding with hydrogen molecules held by weak electrical attraction.

At a Glance

crystal summary

Related Questions

How are point groups different from space groups in crystallography?
How are the axes arranged in the hexagonal crystal system?
How are the axes arranged in the isometric crystal system?
How are the axes arranged in the orthorhombic crystal system?
How are the axes arranged in the tetragonal crystal system?
How are vacancies different from interstitial defects in crystals?
How do chromium impurities give ruby its red color?
How do covalent bonds form in silicon and diamond crystals?
How do crystal defects influence a material’s mechanical, electrical, and optical behavior?
How do crystalline solids differ from amorphous solids such as glass?
How do grain boundaries form in polycrystalline materials?
How do hydrogen bonds hold ice crystals together?
How do ionic bonds hold sodium chloride crystals together?
How do iron and titanium impurities give sapphire its blue color?
How do isotropic crystals affect transmitted plane-polarized light?
How do metallic bonds allow metals to conduct electricity?
How do polarizers help scientists study thin sections of minerals?
How do the structures and properties of diamond and graphite differ even though both are made of carbon?
How does a Frenkel defect form in an ionic crystal?
How does a Schottky defect form in an ionic crystal?
How does a mirror plane create reflection symmetry in a crystal?
How does a vacancy change the electrical and optical properties of a crystal?
How does an impurity atom fit into a crystal lattice?
How does bond strength affect a crystal’s hardness and melting point?
How does graphite’s crystal structure make it useful as a lubricant?
How does optical crystallography help identify minerals in rocks?
How does rapid cooling from a melt make a material amorphous?
How does rotoinversion combine rotation and inversion in a crystal?
What are conduction electrons in a metal crystal?
What are the 14 Bravais lattices used to describe?
Why are covalent bonds highly directional?
Why are graphite layers able to slide past one another?
Why are impurities deliberately added to silicon used in integrated circuits?
Why are only onefold, twofold, threefold, fourfold, and sixfold rotations compatible with ordinary crystal lattices?
Why can hydrogen bonding occur with nitrogen, oxygen, and fluorine?
Why do ionic crystals often have high melting points?
Why do solid ionic crystals conduct electricity poorly while melts and solutions can conduct it?
Why do some sources list six crystal systems while others list seven?
Why do uniaxial crystals produce two refractive indices?
Why does diamond not conduct electricity?
Why does periclase have a much higher melting point than halite despite having a similar structure?
Why does rolling or hammering a metal make it harder?

Science Physics Matter & Energy

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External Websites

DigitalCommons at University of Nebraska - Lincoln - Crystal Structure and DzyaloshinskiÂ–Moriya Micromagnetics (PDF)
Indiana Unversity Pressbooks - Virtual Chemistry Experiments - The Structure of Crystalline Solids
University of Nebraskaï¿½Lincoln - Crystal Structure
University of California Berkeley - College of Natural Resources - What is a Crystal?
Chemistry LibreTexts - Introduction to Crystals
Live Science - Crystal healing: Stone-cold facts about gemstone treatments
California Institute of Technology - The Feynman Lectures on Physics - The Internal Geometry of Crystals
Sri Venkateswara College Of Engineering - Crystal Physics

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

crystal - Children's Encyclopedia (Ages 8-11)
crystals - Student Encyclopedia (Ages 11 and up)

crystal

physics

Also known as: crystal structure, crystalline solid

Written by

Gerald D. Mahan

Distinguished Professor of Physics, Pennsylvania State University, State College, Pa. Distinguished Scientist, Solid State Division, Oak Ridge National Laboratory, Tennessee. Author of Many-Particle...

Gerald D. Mahan

Fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

Britannica Editors

Last updated

Oct. 16, 2026 •History

crystal, any solid material in which the component atoms are arranged in a definite pattern and whose surface regularity reflects its internal symmetry. The definition of a solid appears obvious; a solid is generally thought of as being hard and firm. Upon inspection, however, the definition becomes less straightforward. A cube of butter, for example, is hard after being stored in a refrigerator and is clearly a solid. After remaining on the kitchen counter for...

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