AllTheoretical dataCrystal lattice

Main article: Crystal lattice.

Crystal structure - the infinite three-dimensional periodic lattice that is composed from substances` particles (such as molecules, atoms, etc.)
Crystal lattice - the elementary three-dimensional cell of crystal structure which completely determines its properties. In the general case it is a slanted parallelepiped (sometimes more than one) from the particles which are located in its nodes, edges, etc.

Lattice classification

There are many classifications of crystal lattices - by particle type (chemical), by lattice common shape (singony), by type of symmetry of the lattice (crystal system), by type of spatial translations (Bravais lattice), etc.
There you can find only the basic classifications.


In the chemical classification lattices are combined into four kinds by the type of the constituent particles.

Lattice type Lattice nodes Examples Model
Atomic Atoms of nonmetal elements Diamond, graphite, selenium Grid.atomic.jpg
Molecular Molecules of non-ionic compounds Water, carbon dioxide, sucrose Grid.molecular.jpg
Ionic Cations and anions of salts, acids, alkalines Table salt, citric acid, copper(II) sulfate Grid.ionic.jpg
Metallic Atom-ions of metal elements and their shared electrons Iron, copper, lead, nickel Grid.metallic.jpg

Crystal system, singony, system of lattice

Main atricle: Crystal system (wikipedia).
Main atricle: Crystal system.

The crystal system classification focuses on sets of axes which the lattice can be rotated around less than 360 ° and combined with the non-rotaned one.
The syngony classification focuses on lattices with similar angles and specific distances between nodes.
The system of lattice classification focuses on lattices` symmetry types.

Despite the fact that the defined parameters of all three classification systems are completely different, geometric properties of crystal shapes allow to almost clearly establish the correspondence between them. They are often used as synonyms for each other as they describe finite lattices approximately the same way.

Notice that in Crystal growing project pages all of these terms mean crystal system.

Symmetry category Singony Crystal system System of lattice Count of matches by rotating around the symmetry axis Count of symmetry axises Model
Low symmetric Triclinic None None Singony.triclinic.png
Monoclinic Two One Singony.monoclinic.png
Orthorhombic Two Three Singony.orthorhombic.png
Medium symmetric Tetragonal Four One Singony.tetragonal.png
Hexagonal Trigonal Rhombohedral Three One Singony.rhombohedral.png
Hexagonal Six One Singony.hexagonal.png
High symmetric Cubic Four Three Singony.cubic.png

Crystal shape

Main article: Form.

There you can find all existing 47 simple forms of crystals depending on the crystal system.
It is worth noting that crystals rarely grow in their simplest form, there are often various counterparts, truncation, beveled edges and many other distortions can be found.

Symmetry category Singonies Typical form
Low symmetric Triclinic Forms.low-symmetric.png
Medium symmetric Trigonal Forms.medium-symmetric.prism.png

Forms.medium-symmetric.pyramid.png Forms.medium-symmetric.bipyramid.png Forms.medium-symmetric.simple.png Forms.medium-symmetric.trapezohedron.png

High symmetric Cubic Forms.high-symmetric.png

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