Atomic Number: 109
Atomic Mass: 266.0 amu atomic mass units
Melting Point: Unknown
Boiling Point: Unknown
Number of Protons: 109
Number of Electrons: 109
Number of Neutrons: 157
Classification: Transition Metal Man made
Crystal Structure: Unknown
Density @ 293 K: Unknown
Meitnerium is a radioactive man made super-heavy element. It was first produced in 1982 by a team of scientists led by Peter Armbruster and Gottfried Mnzenber working in the Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, Germany. This laboratory has been instrumental in producing a number of the super-heavy elements. Super-heavy elements are those whose atomic numbers are in excess of 104.
To produce element 109 they used the UNILAC heavy ion accelerator based at the GSI to bombard a target made of atoms of bismuth-209 with ions of iron-58. The high speed impact of these ions can overcome the repulsive forces that normally keep the nuclei of such atoms apart and make them to combine to form a new so called super-heavy element. It took a week of bombardment of the target to produce a single atom of meitnerium. When this atom of the new element was produced a free neutron was also released. The isotope produced in this experiment was found to be meitnerium-266.
The International Union for Pure and Applied Chemistry (IUPAC) gave element the holding name of unnilennium and the symbol Une. Unnilennium relates to the elements atomic number un-nil-enn standing for 1-0-9. The final name for the element comes from that of the Nobel Prize winning Austrian physicist Lise Meitner.
The first isotope of the element produced, meitnerium-266, has a half-life of 3.8 milliseconds. Since it was first made four other isotopes of meitnerium have been made. No stable isotopes of meitnerium have been formed. Meitnerium-276 is the most stable isotope to be produced to date; it decays by alpha decay to form bohrium-272 and has a half-life of 0.72 seconds. The other three isotopes are meitnerium-267, meitnerium-268 and meitnerium-275
With so few atoms being made in these types of experiments and those that are being produced having such short half-lives very little of the chemistry of meitnerium is known. From its position in the periodic table it should be metallic and either silver-white or gray in color.
Super-heavy elements such as meitnerium are unlikely to ever have any industrial usages. The expensive method of manufacture of such atoms along with their short half-lives makes them unsuitable for anything but scientific research.