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Meitnerium

physical science Maturity 11-13 Next article →

Meitnerium is a synthetic chemical element with the symbol Mt and atomic number 109. It is a transactinide element located in the d-block of the periodic table. Being synthetic means it does not occur naturally in the world. Instead, scientists must create it through intense laboratory processes. Meitnerium is extremely radioactive and highly unstable. This instability means its atoms break apart very quickly after they are created.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony

To create meitnerium, scientists use a process called bombardment. In August 1982, a German research team led by Peter Armbruster and Gottfried Münzenberg performed this task. They worked at the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. The team used accelerated nuclei of iron-58 to strike a target made of bismuth-209. This collision resulted in the detection of a single atom of the isotope meitnerium-266. This discovery was confirmed three years later at the Joint Institute for Nuclear Research in the Soviet Union.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony

Scientists study different versions of an element called isotopes. Each isotope has a different number of neutrons. Meitnerium has several reported isotopes, including mass numbers 266, 268, 270, and 274 through 278. Most of these isotopes decay through alpha decay, where the nucleus emits particles. Some also undergo spontaneous fission, which is when the nucleus splits apart. The stability of these isotopes varies significantly. Generally, heavier isotopes are more stable than lighter ones. The most stable confirmed isotope is meitnerium-278, which has a half-life of 4.5 seconds. An unconfirmed isotope, meitnerium-282, might last as long as 67 seconds.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony

The element was named in honor of the Austrian-Swedish nuclear physicist Lise Meitner. She was a co-discoverer of protactinium and one of the discoverers of nuclear fission. The GSI team suggested the name in September 1992. It was recommended by IUPAC in 1994 and officially adopted in 1997. Meitnerium holds a unique place in science as the only element named specifically after a non-mythological woman.

Lise Meitner (1878-1968), lecturing at Catholic University, Washington, D.C., 1946
Lise Meitner (1878-1968), lecturing at Catholic University, Washington, D.C., 1946

Because meitnerium is so difficult and expensive to produce, its physical properties remain largely theoretical. Scientists use calculations to predict how it will behave. Meitnerium is expected to be a heavy, solid metal under normal conditions. It should have a face-centered cubic crystal structure, similar to its neighbor iridium. Its density is predicted to be around 27 to 28 grams per cubic centimeter. This would make it one of the densest of the 118 known elements. It is also expected to be paramagnetic, meaning it is weakly attracted to magnetic fields.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony

Chemically, meitnerium is the seventh member of the 6d series of transition metals. It belongs to group 9 of the periodic table. Scientists believe it will behave like its lighter homologues, which are elements in the same group. These include cobalt, rhodium, and iridium. Meitnerium is expected to be a noble metal. It may show stable oxidation states of +6, +3, and +1. The +3 state is predicted to be the most stable in aqueous solutions. Some theories even suggest a +9 oxidation state might be possible in specific compounds.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony

Despite these predictions, meitnerium is the first element on the periodic table whose chemistry has not been fully investigated. To study the chemistry of a transactinide, researchers face massive obstacles. They must produce at least four atoms and ensure the isotope has a half-life of at least one second. Furthermore, the production rate must be at least one atom per week. While meitnerium-278 lasts 4.5 seconds, the low production rate makes long-term experiments difficult. Future studies might use automated systems to study its behavior in gas or liquid. Researchers hope to use techniques similar to those used for elements like bohrium and hassium.

Bohrium hassium meitnerium ceremony
Bohrium hassium meitnerium ceremony
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File:Lise Meitner (1878-1968), lecturing at Catholic University, Washington, D.C., 1946.jpg
Lise Meitner (1878-1968), lecturing at...
File:Bohrium hassium meitnerium ceremony.jpg
Bohrium hassium meitnerium ceremony.jpg
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