State of matter

In <a href="/facts/Physics/a7aH2y08">physics</a>, a state of matter or phase of matter is one of the distinct forms in which <a href="/facts/Matter/osyc04UN">matter</a> can exist. Four states of matter are observable in everyday life: <a href="/facts/Solid/YU0hJq6f">solid</a>, <a href="/facts/Liquid/t9GkLWzt">liquid</a>, <a href="/facts/Gas/hVVAoodV">gas</a>, and <a href="/facts/Plasma_(physics)/1d3btMVU">plasma</a>.
Different states are distinguished by the ways the component particles (<a href="/facts/Atoms/FoQ4kGN5">atoms</a>, <a href="/facts/Molecules/N9ljSfFq">molecules</a>, <a href="/facts/Ions/fXGhgbFc">ions</a> and <a href="/facts/Electrons/L0KBo5cW">electrons</a>) are arranged, and how they behave collectively. In a solid, the particles are tightly packed and held in fixed positions, giving the material a definite shape and <a href="/facts/Volume/aeAXCBUd">volume</a>. In a liquid, the particles remain close together but can move past one another, allowing the substance to maintain a fixed volume while adapting to the shape of its container. In a gas, the particles are far apart and move freely, allowing the substance to expand and fill both the shape and volume of its container. Plasma is similar to a gas, but it also contains charged particles (ions and free electrons) that move independently and respond to electric and magnetic fields.
Beyond the classical states of matter, a wide variety of additional states are known to exist. Some of these lie between the traditional categories; for example, <a href="/facts/Liquid_crystal/ehCCST89">liquid crystals</a> exhibit properties of both solids and liquids. Others represent entirely different kinds of ordering. <a href="/facts/Magnetic_ordering/eo75vApl">Magnetic states</a>, for instance, do not depend on the spatial arrangement of atoms, but rather on the alignment of their intrinsic magnetic moments (<a href="/facts/Spin_(physics)/4Jvp7e8P">spins</a>). Even in a solid where atoms are fixed in position, the spins can organize in distinct ways, giving rise to magnetic states such as <a href="/facts/Ferromagnetism/fH3HFnSl">ferromagnetism</a> or <a href="/facts/Antiferromagnetism/aQ124Kh7">antiferromagnetism</a>.
Some states occur only under extreme conditions, such as <a href="/facts/Bose%25E2%2580%2593Einstein_condensate/76peCwfW">Bose–Einstein condensates</a> and <a href="/facts/Fermionic_condensate/WlqsAJtp">Fermionic condensates</a> (in extreme cold), <a href="/facts/Neutron-degenerate_matter/S5bc5MwK">neutron-degenerate matter</a> (in extreme density), and <a href="/facts/Quark%25E2%2580%2593gluon_plasma/TQ8RPydR">quark–gluon plasma</a> (at extremely <a href="/facts/High-energy_nuclear_physics/1V75JrJK">high energy</a>).
The term <a href="/facts/Phase_(matter)/NkHXDdN3">phase</a> is sometimes used as a <a href="/facts/Synonym/a3BgMcdu">synonym</a> for state of matter, but it is possible for a single compound to form different phases that are in the same state of matter. For example, <a href="/facts/Ice/BGvkKFjD">ice</a> is the solid state of water, but there are multiple <a href="/facts/Phases_of_ice/BGvkKFjD">phases of ice</a> with different <a href="/facts/Crystal_structure/bJ4bCeHd">crystal structures</a>, which are formed at different pressures and temperatures.

State of matter open-in-new

State of matter