Magnesium diboride

Information about Magnesium diboride

Systematic name
Molecular formulaMgB2
Molar mass45.93 g/mol
Density2.6 g/cm3
Solubility (water)x.xx g/l
Melting point1300 °C (decomp.)
Boiling pointxx.x °C
CAS number[12007-25-9]
Magnesium diboride (MgB2) is an inexpensive and simple superconductor. Its superconductivity was announced in the journal Nature in March 2001[1]. Its critical temperature (39 K) is the highest amongst conventional superconductors (phonon-mediated superconductors). This material was first synthesized in 1953 but its superconducting properties were not discovered until half a century later.

Though a conventional superconductor, it is a rather unusual one. Its electronic structure is such that there exist two types of electrons at the Fermi level with widely differing behaviours, one of them being much more strongly superconducting than the other. This is at odds with usual theories of phonon-mediated superconductivity which assume that all electrons behave in the same manner. For this reason, theoretical understanding of the properties of MgB2 has not yet been achieved, particularly so in the presence of a magnetic field.

Magnesium diboride can be synthesized by several routes, the simplest is by high temperature reaction between boron and magnesium powders. Formation begins at 650 Celsius, however, since Magnesium metal melts at 652 Celsius, the reaction mechanism is considered to be moderated by magnesium vapor diffusion across boron grain boundaries. At conventional reaction temperatures, sintering is minimal, although enough grain recrystallization occurs to permit Josephson Quantum tunnelling between grains.

Engineering wire production is typically via the Powder In Tube process. Either (in-situ) a mixture of boron and magnesium is poured into a metal tube, or (ex-situ) magnesium diboride powder is poured into a tube. In both cases, the tube is reduced in diameter to form a wire by conventional wire drawing processes. Then the finished wire is heat-treated, either at the reaction temperature (in-situ) or at approximately 800 to 1000 degrees Celsius (ex situ). The ex-situ heat treatment is a conventional sintering process. In both cases, later hot isostatic pressing at approximately 950 degrees Celsius further improves the properties.

Its superconducting properties and cheapness make it useful for a variety of applications. Recently, a cryogenic-free 0.5 Tesla open MRI system has been successfully designed and built using 18 Km of MgB2 conductors. Thin coatings can be used in superconducting radio frequency cavities to minimize energy loss and reduce the inefficiency of liquid helium cooled niobium cavities. Due to the low cost of its constituent materials, MgB2, has promise for use in superconducting low/medium field magnets, electric motors and generators, fault current limiters and current leads. The relatively low working temperature (compared with high temperature superconductors) means that cooling costs make it an unlikely candidate for power lines, although the hope in the future Hydrogen technology could enable the use of MgB2 in this sector as well.

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IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. It is developed and kept up to date under the auspices of the International Union of Pure and Applied Chemistry (IUPAC).
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A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. A chemical formula is also a short way of showing how a chemical reaction occurs.
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Molar mass, symbol M,[1] is the mass of one mole of a substance (chemical element or chemical compound).[2] It is a physical property which is characteristic of each pure substance.
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In physics, density is mass m per unit volume V—how heavy something is compared to its size. A small, heavy object, such as a rock or a lump of lead, is denser than a lighter object of the same size or a larger object of the same weight, such as pieces of
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Solubility is a physical property referring to the ability for a given substance, the solute, to dissolve in a solvent.[1] It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.
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The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds
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boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid.[1][2][3][4]
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CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. They are also referred to as CAS numbers, CAS RNs or CAS #s.
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Superconductivity is a phenomenon occurring in certain materials at extremely low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect).
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journal (through French from late Latin diurnalis, daily) has several related meanings:
  • a daily record of events or business; a private journal is usually referred to as a diary.

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The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero — the coldest possible temperature — is zero kelvins
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Conventional superconductors are materials that display superconductivity as described by BCS theory or its extensions.(c.f. Unconventional superconductor)

Critical temperatures of some simple metals:
Element Tc (K)
Al 1.20
Hg 4.15
Mo 0.
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phonon is a quantized mode of vibration occurring in a rigid crystal lattice, such as the atomic lattice of a solid.[1] The study of phonons is an important part of solid state physics, because phonons play a major role in many of the physical properties of solids,
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The Fermi energy is a concept in quantum mechanics referring to the energy of the highest occupied quantum state in a system of fermions at absolute zero temperature. This article requires a basic knowledge of quantum mechanics.
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magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles. Magnetic fields surround electric currents, magnetic dipoles, and changing electric fields.
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This article is about the physical mechanism of diffusion. For alternative meanings, see diffusion (disambiguation).


Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
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Sintering is a method for making objects from powder, by heating the material (below its melting point) until its particles adhere to each other. Sintering is traditionally used for manufacturing ceramic objects, and has also found uses in such fields as powder metallurgy.
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In quantum mechanics, quantum tunnelling is a micro and nanoscopic phenomenon in which a particle violates principles of classical mechanics by penetrating or passing through a potential barrier or impedance higher than the kinetic energy of the particle.
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