This is a list of the different states of matter including the more exotic ones (see phases of matter).

Generally states of matter are distinguished by the pressure and temperature, transforming into other states as conditions change to favor existence of the other form, an example is melting and its complement freezing.

• Solid: A solid holds a rigid shape.
• Liquid: A non-compressible fluid. Able to conform to the shape of its container but retaining a (nearly) constant volume independent of pressure.
• Gas: A compressible fluid. Not only will a gas conform to the shape of its container but it will expand or compress to fill the container.
• Plasma: A gas in which electrons can become free of their atoms resulting in a distribution of charges able to conduct electricity.
• Superfluid: A state achieved by a few cryogenic liquids at extreme temperature where they become able to flow without friction. A superfluid can flow up the side of an open container and down the outside. Placing a superfluid in a spinning container will result in quantized vortices.
• Supersolid: similar to a superfluid, a supersolid is able to move without friction but retains a rigid shape.
• Degenerate matter: found in the crust of white dwarf stars. Electrons remain bound to atoms but are able to transfer to adjacent atoms.
• Neutronium: found in neutron stars. Vast gravitational pressure compresses atoms so hard the electrons are forced into the nucleus, resulting in a superdense conglomeration of neutrons. (Normally neutrons decay with a half life of about 15 minutes, but in a neutron star, as in the nucleus of an atom, other effects stabilize the neutrons.)
• Strongly symmetric matter : for less than a second after the Big Bang the energy density of the universe was so high that the four forces of nature, strong, weak, electromagnetic, and gravitational, were unified into one single force. Then the universe expanded, the temperature and density dropped, and the strong force separated, a process called symmetry breaking.
• Weakly symmetric matter : for three to four minutes after the Big Bang the weak, electromagnetic, and gravitational forces were unified.
• Bose-Einstein condensate: a state in which a large number of bosons all inhabit the same quantum state, in effect becoming one single wave/particle.
• Fermionic condensate: Similar to the Bose-Einstein condensate but composed of fermions. The Pauli exclusion principle prevents fermions from entering the same quantum state, but by pairing up two fermions can behave as a baryon and the pairs can then enter the same quantum state without restrictions.
• Quark-gluon plasma: A state in which quarks become free and able to move independently (rather than being perpetually bound into particles) in a sea of gluons (subatomic particles that transmit the strong force that binds quarks together). May be briefly attainable in particle accelerators.
• Strange matter: (aka Quark matter) which may be found inside some particularly large neutron stars.