Crystals of amethyst quartz
Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)
Microscopically, a single crystal has atoms in a near-perfect periodic arrangement; a polycrystal is composed of many microscopic crystals (called "crystallites" or "grains"); and an amorphous solid (such as glass) has no periodic arrangement even microscopically.
The Geiger–Marsden experiment:
Left: Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.
Right: Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.
As a halite crystal is growing, new atoms can very easily attach to the parts of the surface with rough atomic-scale structure and many dangling bonds. Therefore, these parts of the crystal grow out very quickly (yellow arrows). Eventually, the whole surface consists of smooth, stable faces, where new atoms cannot as easily attach themselves.
The Bohr model of the atom, with an electron making instantaneous "quantum leaps" from one orbit to another with gain or loss of energy. This model of electrons in orbits is obsolete.
Ice crystals
The binding energy needed for a nucleon to escape the nucleus, for various isotopes
Fossil shell with calcite crystals
A potential well, showing, according to classical mechanics, the minimum energy V(x) needed to reach each position x. Classically, a particle with energy E is constrained to a range of positions between x1 and x2.
Vertical cooling crystallizer in a beet sugar factory.
3D views of some hydrogen-like atomic orbitals showing probability density and phase (g orbitals and higher are not shown)
Two types of crystallographic defects. Top right: edge dislocation. Bottom right: screw dislocation.
This diagram shows the half-life (T½) of various isotopes with Z protons and N neutrons.
Twinned pyrite crystal group.
These electron's energy levels (not to scale) are sufficient for ground states of atoms up to cadmium (5s2 4d10) inclusively. Do not forget that even the top of the diagram is lower than an unbound electron state.
The material holmium–magnesium–zinc (Ho–Mg–Zn) forms quasicrystals, which can take on the macroscopic shape of a pentagonal dodecahedron. Only quasicrystals can take this 5-fold symmetry. The edges are 2 mm long.
An example of absorption lines in a spectrum
Insulin crystals grown in earth orbit.
Graphic illustrating the formation of a Bose–Einstein condensate
Hoar frost: A type of ice crystal (picture taken from a distance of about 5 cm).
Scanning tunneling microscope image showing the individual atoms making up this gold (100) surface. The surface atoms deviate from the bulk crystal structure and arrange in columns several atoms wide with pits between them (See surface reconstruction).
Gallium, a metal that easily forms large crystals.
Periodic table showing the origin of each element. Elements from carbon up to sulfur may be made in small stars by the alpha process. Elements beyond iron are made in large stars with slow neutron capture (s-process). Elements heavier than iron may be made in neutron star mergers or supernovae after the r-process.
An apatite crystal sits front and center on cherry-red rhodochroite rhombs, purple fluorite cubes, quartz and a dusting of brass-yellow pyrite cubes.
Boules of silicon, like this one, are an important type of industrially-produced single crystal.
A specimen consisting of a bornite-coated chalcopyrite crystal nestled in a bed of clear quartz crystals and lustrous pyrite crystals. The bornite-coated crystal is up to 1.5 cm across.
Needle-like millerite crystals partially encased in calcite crystal and oxidized on their surfaces to zaratite; from the Devonian Milwaukee Formation of Wisconsin

A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

- Crystal

Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules or crystals.

- Atom
Crystals of amethyst quartz

5 related topics

Alpha

Examples of Lewis dot-style representations of chemical bonds between carbon (C), hydrogen (H), and oxygen (O). Lewis dot diagrams were an early attempt to describe chemical bonding and are still widely used today.

Chemical bond

Compare molecular binding, which often includes chemical bonding.

Compare molecular binding, which often includes chemical bonding.

Examples of Lewis dot-style representations of chemical bonds between carbon (C), hydrogen (H), and oxygen (O). Lewis dot diagrams were an early attempt to describe chemical bonding and are still widely used today.
Crystal structure of sodium chloride (NaCl) with sodium cations in and chloride anions  in . The yellow stipples represent the electrostatic force between the ions of opposite charge.
Non-polar covalent bonds in methane (CH4). The Lewis structure shows electrons shared between C and H atoms.
Two p-orbitals forming a pi-bond.
Adduct of ammonia and boron trifluoride

A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.

The atoms in molecules, crystals, metals and diatomic gases—indeed most of the physical environment around us—are held together by chemical bonds, which dictate the structure and the bulk properties of matter.

Theoretically predicted phase diagram of carbon, from 1989. Newer work indicates that the melting point of diamond (top-right curve) does not go above about 9000 K.

Carbon

Chemical element with the symbol C and atomic number 6.

Chemical element with the symbol C and atomic number 6.

Theoretically predicted phase diagram of carbon, from 1989. Newer work indicates that the melting point of diamond (top-right curve) does not go above about 9000 K.
A large sample of glassy carbon
Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d–f) fullerenes (C60, C540, C70); g) amorphous carbon; h) carbon nanotube
Comet C/2014 Q2 (Lovejoy) surrounded by glowing carbon vapor
Graphite ore, shown with a penny for scale
Raw diamond crystal
"Present day" (1990s) sea surface dissolved inorganic carbon concentration (from the GLODAP climatology)
Diagram of the carbon cycle. The black numbers indicate how much carbon is stored in various reservoirs, in billions tonnes ("GtC" stands for gigatonnes of carbon; figures are circa 2004). The purple numbers indicate how much carbon moves between reservoirs each year. The sediments, as defined in this diagram, do not include the ≈70 million GtC of carbonate rock and kerogen.
Structural formula of methane, the simplest possible organic compound.
Correlation between the carbon cycle and formation of organic compounds. In plants, carbon dioxide formed by carbon fixation can join with water in photosynthesis ( green ) to form organic compounds, which can be used and further converted by both plants and animals.
This anthracene derivative contains a carbon atom with 5 formal electron pairs around it.
Antoine Lavoisier in his youth
Carl Wilhelm Scheele
Diamond output in 2005
Pencil leads for mechanical pencils are made of graphite (often mixed with a clay or synthetic binder).
Sticks of vine and compressed charcoal
A cloth of woven carbon fibres
Silicon carbide single crystal
The C60 fullerene in crystalline form
Tungsten carbide endmills
Worker at carbon black plant in Sunray, Texas (photo by John Vachon, 1942)

It bonds readily with other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with suitable multivalent atoms.

Although a computational study employing density functional theory methods reached the conclusion that as T → 0 K and p → 0 Pa, diamond becomes more stable than graphite by approximately 1.1 kJ/mol, more recent and definitive experimental and computational studies show that graphite is more stable than diamond for T < 400 K, without applied pressure, by 2.7 kJ/mol at T = 0 K and 3.2 kJ/mol at T = 298.15 K. Under some conditions, carbon crystallizes as lonsdaleite, a hexagonal crystal lattice with all atoms covalently bonded and properties similar to those of diamond.

Hydrogen atom (center) contains a single proton and a single electron. Removal of the electron gives a cation (left), whereas the addition of an electron gives an anion (right). The hydrogen anion, with its loosely held two-electron cloud, has a larger radius than the neutral atom, which in turn is much larger than the bare proton of the cation. Hydrogen forms the only charge-+1 cation that has no electrons, but even cations that (unlike hydrogen) retain one or more electrons are still smaller than the neutral atoms or molecules from which they are derived.

Ion

Hydrogen atom (center) contains a single proton and a single electron. Removal of the electron gives a cation (left), whereas the addition of an electron gives an anion (right). The hydrogen anion, with its loosely held two-electron cloud, has a larger radius than the neutral atom, which in turn is much larger than the bare proton of the cation. Hydrogen forms the only charge-+1 cation that has no electrons, but even cations that (unlike hydrogen) retain one or more electrons are still smaller than the neutral atoms or molecules from which they are derived.
Schematic of an ion chamber, showing drift of ions. Electrons drift faster than positive ions due to their much smaller mass.
Avalanche effect between two electrodes. The original ionization event liberates one electron, and each subsequent collision liberates a further electron, so two electrons emerge from each collision: the ionizing electron and the liberated electron.
Equivalent notations for an iron atom (Fe) that lost two electrons, referred to as ferrous.
Mixed Roman numerals and charge notations for the uranyl ion. The oxidation state of the metal is shown as superscripted Roman numerals, whereas the charge of the entire complex is shown by the angle symbol together with the magnitude and sign of the net charge.
An electrostatic potential map of the nitrate ion . The 3-dimensional shell represents a single arbitrary isopotential.

An ion is an atom or molecule with a net electrical charge.

Cations and anions are measured by their ionic radius and they differ in relative size: "Cations are small, most of them less than 10−10 m (10−8 cm) in radius. But most anions are large, as is the most common Earth anion, oxygen. From this fact it is apparent that most of the space of a crystal is occupied by the anion and that the cations fit into the spaces between them."

Crystal structure of table salt (sodium in purple, chloride in green)

Crystal structure

Crystal structure of table salt (sodium in purple, chloride in green)
Planes with different Miller indices in cubic crystals
Dense crystallographic planes
The hcp lattice (left) and the fcc lattice (right)
Quartz is one of the several crystalline forms of silica, SiO2. The most important forms of silica include: α-quartz, β-quartz, tridymite, cristobalite, coesite, and stishovite.
Simple cubic (P)
Body-centered cubic (I)
Face-centered cubic (F)

In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material.

Snowflakes are a very well-known example, where subtle differences in crystal growth conditions result in different geometries.

Crystallization

Snowflakes are a very well-known example, where subtle differences in crystal growth conditions result in different geometries.
Crystallized honey
Low-temperature SEM magnification series for a snow crystal. The crystals are captured, stored, and sputter-coated with platinum at cryo-temperatures for imaging.
Crystal growth
Crystallization of sodium acetate.
Solubility of the system Na2SO4 – H2O
Vertical cooling crystallizer in a beet sugar factory
DTB Crystallizer
Schematic of DTB

Crystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.