State of matter
In
Historically, the distinction is made based on qualitative differences in properties. Matter in the solid state maintains a fixed
The term phase is sometimes used as a synonym 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, ice is the solid state of water, but there are multiple phases of ice with different crystal structures, which are formed at different pressures and temperatures.
Four classical states
Solid
In a solid, constituent particles (ions, atoms, or molecules) are closely packed together. The forces between particles are so strong that the particles cannot move freely but can only vibrate. As a result, a solid has a stable, definite shape, and a definite volume. Solids can only change their shape by an outside force, as when broken or cut.
In crystalline solids, the particles (atoms, molecules, or ions) are packed in a regularly ordered, repeating pattern. There are various different crystal structures, and the same substance can have more than one structure (or solid phase). For example, iron has a body-centred cubic structure at temperatures below 912 °C (1,674 °F), and a face-centred cubic structure between 912 and 1,394 °C (2,541 °F). Ice has fifteen known crystal structures, or fifteen solid phases, which exist at various temperatures and pressures.[1]
Solids can be transformed into liquids by melting, and liquids can be transformed into solids by freezing. Solids can also change directly into gases through the process of
Liquid
A liquid is a nearly incompressible
Gas
A gas is a compressible fluid. Not only will a gas conform to the shape of its container but it will also expand to fill the container.
In a gas, the molecules have enough kinetic energy so that the effect of intermolecular forces is small (or zero for an ideal gas), and the typical distance between neighboring molecules is much greater than the molecular size. A gas has no definite shape or volume, but occupies the entire container in which it is confined. A liquid may be converted to a gas by heating at constant pressure to the boiling point, or else by reducing the pressure at constant temperature.
At temperatures below its
A
Plasma
A gas is usually converted to a plasma in one of two ways, either from a huge voltage difference between two points, or by exposing it to extremely high temperatures. Heating matter to high temperatures causes electrons to leave the atoms, resulting in the presence of free electrons. This creates a so-called partially ionised plasma. At very high temperatures, such as those present in stars, it is assumed that essentially all electrons are "free", and that a very high-energy plasma is essentially bare nuclei swimming in a sea of electrons. This forms the so-called fully ionised plasma.
The plasma state is often misunderstood, and although not freely existing under normal conditions on Earth, it is quite commonly generated by either
Phase transitions
A state of matter is also characterized by
To From
|
Solid | Liquid | Gas | Plasma |
---|---|---|---|---|
Solid | Melting | Sublimation | ||
Liquid | Freezing | Vaporization | ||
Gas | Deposition | Condensation | Ionization | |
Plasma | Recombination |
The state or phase of a given set of matter can change depending on
Forms of matter that are not composed of molecules and are organized by different forces can also be considered different states of matter.
In a chemical equation, the state of matter of the chemicals may be shown as (s) for solid, (l) for liquid, and (g) for gas. An aqueous solution is denoted (aq). Matter in the plasma state is seldom used (if at all) in chemical equations, so there is no standard symbol to denote it. In the rare equations that plasma is used it is symbolized as (p).
Non-classical states
Glass
Crystals with some degree of disorder
A
Similarly, in a spin glass magnetic disorder is frozen.
Liquid crystal states
Liquid crystal states have properties intermediate between mobile liquids and ordered solids. Generally, they are able to flow like a liquid, but exhibiting long-range order. For example, the
Other types of liquid crystals are described in the main article on these states. Several types have technological importance, for example, in
Microphase separation
Ionic liquids also display microphase separation. The anion and cation are not necessarily compatible and would demix otherwise, but electric charge attraction prevents them from separating. Their anions and cations appear to diffuse within compartmentalized layers or micelles instead of freely as in a uniform liquid.[11]
Magnetically ordered states
Transition metal atoms often have magnetic moments due to the net spin of electrons that remain unpaired and do not form chemical bonds. In some solids the magnetic moments on different atoms are ordered and can form a ferromagnet, an antiferromagnet or a ferrimagnet.
In a
An antiferromagnet has two networks of equal and opposite magnetic moments, which cancel each other out so that the net magnetization is zero. For example, in nickel(II) oxide (NiO), half the nickel atoms have moments aligned in one direction and half in the opposite direction.
In a ferrimagnet, the two networks of magnetic moments are opposite but unequal, so that cancellation is incomplete and there is a non-zero net magnetization. An example is magnetite (Fe3O4), which contains Fe2+ and Fe3+ ions with different magnetic moments.
A quantum spin liquid (QSL) is a disordered state in a system of interacting quantum spins which preserves its disorder to very low temperatures, unlike other disordered states. It is not a liquid in physical sense, but a solid whose magnetic order is inherently disordered. The name "liquid" is due to an analogy with the molecular disorder in a conventional liquid. A QSL is neither a ferromagnet, where magnetic domains are parallel, nor an antiferromagnet, where the magnetic domains are antiparallel; instead, the magnetic domains are randomly oriented. This can be realized e.g. by geometrically frustrated magnetic moments that cannot point uniformly parallel or antiparallel. When cooling down and settling to a state, the domain must "choose" an orientation, but if the possible states are similar in energy, one will be chosen randomly. Consequently, despite strong short-range order, there is no long-range magnetic order.
Superfluids and condensates
Superconductor
Superconductors are materials which have zero electrical resistivity, and therefore perfect conductivity. This is a distinct physical state which exists at low temperature, and the resistivity increases discontinuously to a finite value at a sharply-defined transition temperature for each superconductor.[12]
A superconductor also excludes all magnetic fields from its interior, a phenomenon known as the Meissner effect or perfect diamagnetism.[12] Superconducting magnets are used as electromagnets in magnetic resonance imaging machines.
The phenomenon of superconductivity was discovered in 1911, and for 75 years was only known in some metals and metallic alloys at temperatures below 30 K. In 1986 so-called high-temperature superconductivity was discovered in certain ceramic oxides, and has now been observed in temperatures as high as 164 K.[13]
Superfluid
Close to absolute zero, some liquids form a second liquid state described as superfluid because it has zero
These properties are explained by the theory that the common isotope helium-4 forms a Bose–Einstein condensate (see next section) in the superfluid state. More recently, fermionic condensate superfluids have been formed at even lower temperatures by the rare isotope helium-3 and by lithium-6.[15]
Bose–Einstein condensate
In 1924, Albert Einstein and Satyendra Nath Bose predicted the "Bose–Einstein condensate" (BEC), sometimes referred to as the fifth state of matter. In a BEC, matter stops behaving as independent particles, and collapses into a single quantum state that can be described with a single, uniform wavefunction.
In the gas phase, the Bose–Einstein condensate remained an unverified theoretical prediction for many years. In 1995, the research groups of
Fermionic condensate
A fermionic condensate is similar to the Bose–Einstein condensate but composed of fermions. The Pauli exclusion principle prevents fermions from entering the same quantum state, but a pair of fermions can behave as a boson, and multiple such pairs can then enter the same quantum state without restriction.
High-energy states
Degenerate matter
Under extremely high pressure, as in the cores of dead stars, ordinary matter undergoes a transition to a series of exotic states of matter collectively known as degenerate matter, which are supported mainly by quantum mechanical effects. In physics, "degenerate" refers to two states that have the same energy and are thus interchangeable. Degenerate matter is supported by the Pauli exclusion principle, which prevents two fermionic particles from occupying the same quantum state. Unlike regular plasma, degenerate plasma expands little when heated, because there are simply no momentum states left. Consequently, degenerate stars collapse into very high densities. More massive degenerate stars are smaller, because the gravitational force increases, but pressure does not increase proportionally.
Electron-degenerate matter is found inside white dwarf stars. Electrons remain bound to atoms but are able to transfer to adjacent atoms. Neutron-degenerate matter is found in neutron stars. Vast gravitational pressure compresses atoms so strongly that the electrons are forced to combine with protons via inverse beta-decay, resulting in a superdense conglomeration of neutrons. Normally free neutrons outside an atomic nucleus will decay with a half life of approximately 10 minutes, but in a neutron star, the decay is overtaken by inverse decay. Cold degenerate matter is also present in planets such as Jupiter and in the even more massive brown dwarfs, which are expected to have a core with metallic hydrogen. Because of the degeneracy, more massive brown dwarfs are not significantly larger. In metals, the electrons can be modeled as a degenerate gas moving in a lattice of non-degenerate positive ions.
Quark matter
In regular cold matter,
Quark–gluon plasma is a very high-temperature phase 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. This is analogous to the liberation of electrons from atoms in a plasma. This state is briefly attainable in extremely high-energy heavy ion collisions in particle accelerators, and allows scientists to observe the properties of individual quarks. Theories predicting the existence of quark–gluon plasma were developed in the late 1970s and early 1980s,[16] and it was detected for the first time in the laboratory at CERN in the year 2000.[17][18] Unlike plasma, which flows like a gas, interactions within QGP are strong and it flows like a liquid.
At high densities but relatively low temperatures, quarks are theorized to form a quark liquid whose nature is presently unknown. It forms a distinct
Color-glass condensate
Color-glass condensate is a type of matter theorized to exist in atomic nuclei traveling near the speed of light. According to Einstein's theory of relativity, a high-energy nucleus appears length contracted, or compressed, along its direction of motion. As a result, the gluons inside the nucleus appear to a stationary observer as a "gluonic wall" traveling near the speed of light. At very high energies, the density of the gluons in this wall is seen to increase greatly. Unlike the quark–gluon plasma produced in the collision of such walls, the color-glass condensate describes the walls themselves, and is an intrinsic property of the particles that can only be observed under high-energy conditions such as those at RHIC and possibly at the Large Hadron Collider as well.
Very high energy states
Various theories predict new states of matter at very high energies. An unknown state has created the
Other proposed states
Supersolid
A supersolid is a spatially ordered material (that is, a solid or crystal) with superfluid properties. Similar to a superfluid, a supersolid is able to move without friction but retains a rigid shape. Although a supersolid is a solid, it exhibits so many characteristic properties different from other solids that many argue it is another state of matter.[19]
String-net liquid
In a string-net liquid, atoms have apparently unstable arrangement, like a liquid, but are still consistent in overall pattern, like a solid. When in a normal solid state, the atoms of matter align themselves in a grid pattern, so that the spin of any electron is the opposite of the spin of all electrons touching it. But in a string-net liquid, atoms are arranged in some pattern that requires some electrons to have neighbors with the same spin. This gives rise to curious properties, as well as supporting some unusual proposals about the fundamental conditions of the universe itself.
Superglass
A superglass is a phase of matter characterized, at the same time, by
Chain-melted state
Metals, like potassium, in the chain-melted state appear to be in the liquid and solid state at the same time. This is a result of being subjected to high temperature and pressure, leading to the chains in the potassium to dissolve into liquid while the crystals remain solid.[20]
Quantum Hall state
A quantum Hall state gives rise to quantized
Photonic matter
Photonic matter is a phenomenon where
See also
- Hidden states of matter
- Classical element
- Condensed matter physics
- Cooling curve
- Phase (matter)
- Supercooling
- Superheating
- List of states of matter
Notes and references
- ^
M.A. Wahab (2005). Solid State Physics: Structure and Properties of Materials. Alpha Science. pp. 1–3. ISBN 978-1-84265-218-3.
- ^
F. White (2003). Fluid Mechanics. McGraw-Hill. p. 4. ISBN 978-0-07-240217-9.
- ^
G. Turrell (1997). Gas Dynamics: Theory and Applications. John Wiley & Sons. pp. 3–5. ISBN 978-0-471-97573-1.
- ^ "Plasma, Plasma, Everywhere". NASA Science. 7 September 1999.
- ISBN 978-3-540-22321-4.
- ISBN 978-3-319-63427-2.
- ^ M. Chaplin (20 August 2009). "Water phase Diagram". Water Structure and Science. Archived from the original on 3 March 2016. Retrieved 23 February 2010.
- ^
D.L. Goodstein (1985). States of Matter. ISBN 978-0-486-49506-4.
- ^
A.P. Sutton (1993). Electronic Structure of Materials. Oxford Science Publications. pp. 10–12. ISBN 978-0-19-851754-2.
- .
- ^ ISBN 0-19-511331-4.
- ISBN 0486435032.
- ^ J.R. Minkel (20 February 2009). "Strange but True: Superfluid Helium Can Climb Walls". Scientific American. Archived from the original on 19 March 2011. Retrieved 23 February 2010.
- ^ L. Valigra (22 June 2005). "MIT physicists create new form of matter". MIT News. Archived from the original on 11 December 2013. Retrieved 23 February 2010.
- ISBN 978-0-444-86227-3.
- arXiv:nucl-th/0002042.
- ISSN 0362-4331. Retrieved 10 May 2020.
- ^
G. Murthy; et al. (1997). "Superfluids and Supersolids on Frustrated Two-Dimensional Lattices". S2CID 119498444.
- ^ Mann, Adam (8 April 2019). "Confirmed: New phase of matter is solid and liquid at same time". National Geographic. Archived from the original on 14 April 2021. Retrieved 13 November 2023.
External links
- 2005-06-22, MIT News: MIT physicists create new form of matter Citat: "... They have become the first to create a new type of matter, a gas of atoms that shows high-temperature superfluidity."
- 2003-10-10, Science Daily: Metallic Phase For Bosons Implies New State Of Matter
- 2004-01-15, ScienceDaily: Probable Discovery Of A New, Supersolid, Phase Of Matter Citat: "...We apparently have observed, for the first time, a solid material with the characteristics of a superfluid...but because all its particles are in the identical quantum state, it remains a solid even though its component particles are continually flowing..."
- 2004-01-29, ScienceDaily: NIST/University Of Colorado Scientists Create New Form Of Matter: A Fermionic Condensate
- Short videos demonstrating of States of Matter, solids, liquids and gases by Prof. J M Murrell, University of Sussex Archived 30 March 2023 at the Wayback Machine