Gourt Home::Gourt :: Magnesium diboride
| Systematic name | |
| Other names | xxx, xxx |
| Molecular formula | XxXxXx |
| Molar mass | xx.xx g/mol |
| Density | x.xxx g/cm3 |
| Solubility (water) | x.xx g/l |
| Melting point | xx.x °C |
| Boiling point | xx.x °C |
| CAS number | * |
| Chemical infobox | |
Formation beings at 650 Celsius. However, since Magnesium metal melts at 651 Celsius, the reaction mechanism is considered to be moderated by magnesium vapor diffusion across boron grain boundaries. At conventional processing temperatures, sintering is minimal, although enough grain recrystallization occurs to permit Josephson Quantum tunnelling. Bulk samples are extremely porous and show poor ceramic properties, yet its superconducting properties make it useful for a variety of applications. Thin coatings can be used in superconducting Radio Frequency Cavities to minimize energy loss and reduce the inefficiency of liqiuid helium cooled niobium cavities. Due to the low cost of its constituent materials, MgB2, has promise for use in superconducting power lines.
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 is not yet achieved, particularly so in the presence of magnetic field.
External links
- Essential Science Indicators on MgB2
- Old material makes a new debut, US Department of Energy Research News
"Magnesium diboride"