Meitnerium

Named after eminent physicist Lise Meitner, Meitnerium (Mt) was first discovered synthetically by Peter Armbruster and Gottfried Münzenber in Darmstadt, Germany. Working at the GSI Helmholtz Centre for Heavy Ion Research Laboratory, the pair came up with the element by bombarding Bismuth-209 with an accelerated Iron-58 nucleus. 

Meitnerium has a few isotopes, out of which Meitnerium-278 has the longest half-life of 4.5 seconds.

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History of Meitnerium

Mt element has a very interesting history associated with it. The element is not a naturally occurring one. It was synthesised under laboratory conditions. 

The team of scientists first accelerated several nuclei of iron-58 and hit them to a target of bismuth-209. After this experiment, they were presented with a single atom of Meitnerium-266. 

The chemical reaction detected was as follows:

20983Bi + 5826Fe → 266109Mt + n

The reaction and the product thus produced was accepted by the scientific community three years later at the Joint Institute for Nuclear Research (Russia).

Naming of the Element

Putting to use Mendeleev’s nomenclature practices, the element was supposed to be named as eka-iridium. Then in 1979, after IUPAC published their own set of rules to name elements and compounds, the element was provided with a makeshift name of unnilennium. But neither of these names were popularly used by textbooks and other communities. Scientists, for most of their experiments, called it 'element 109’ or E109 or even only 109. 

During that decade, a popular debate ensued among chemists regarding the naming of elements of atomic numbers between 104 and 109. It was at this time that the GSI team proposed the name Meitnerium (Mt) in September 1992 to honour the famous Austrian physicist Lise Meitner, who also discovered protactinium along with Otto Hahn and was one of the pioneers for nuclear fission. The name was then accepted by the IUPAC and made official in 1997.

Did You Know?

Meitnerium is the only compound other than Curium, which has been named after a real person and not a mythological character. Curium was named after scientists Marie and Pierre Curie. 

Isotopes of the Element

Since the element is not naturally occurring, there are no stable naturally occurring isotopes of it too. Most of its isotopes have been synthesised inside laboratories and are radioactive. They were done mostly by fusing two of the same atoms or found when heavier atoms were decaying after fission. Till date, there are eight different isotopes of Mt with masses 266, 268, 270 and 274-278.

Owing to the laboratory invention procedure, almost all isotopes of the compound are radioactive and unstable. It has been seen that compounds with heavier nuclei mass are more stable. 

The same goes for Meitnerium too. The most stable isotope, 278Mt, is the heaviest know yet and has a half-life of 4.5 seconds. An even heavier, unconfirmed isotope 282Mt, has a longer half-life of 67 seconds. But other than these, all other isotopes of Mt have a half-life in fractions of seconds. 

The Table Below Lists All The Isotopes of Mt and Other Relevant Information Regarding All of Them.

1. Meitnerium assumes a cubic crystal structure, and similar to iridium. It is face-centred and is predicted to be solid at room temperature.

2. It is supposed to be exceptionally heavy, with a density of 37.4 g/cm3.

3. With this high density, it is expected to be the second most dense of all known 118 elements. It is second only to Hassium which has a density of 41 gm/cm3.

4. The Lanthanide and Actinide contractions, as well as its very high atomic weight, could be some of the factor contributing to its exceptionally high density.

5. It is also supposed to have paramagnetic properties and a very quick rate of decay.

6. Its covalent radius has been predicted to be 6-10 pm larger than iridium.

7. The atomic radius of Meitnerium is around 128 pm.

Atomic and Physical Properties

Meitnerium Chemical Properties and Uses

This rare element and its parent elements show a remarkable rate of decay. Owing to this, the production of Meitnerium is very limited and costly. Its exact properties remain unknown whatsoever, but some predictions state the following probable properties:

1. It is the 7th member, belonging to the 6d series of transition metals. 

2. As is known, copernicium or element number 112 is a metal belonging to Group 12.  It is predicted that all elements from number 104 to 111 would exhibit the properties of fourth transition metal. Meitnerium too forms a part of this series and a component of the platinum group metals. 

3. Scientific research posits the fact that it might resemble Group 9 elements such as cobalt, iridium and rhodium in its properties.

4. Meitnerium also shares similarities with iridium in terms of ionic and atomic radii, as well as ionisation potentials.

5. Not much is known about its chemical properties. It is expected to be a noble metal, by a study of its characteristics and could resemble silver in terms of how noble it is.

6. Predictions about this element's oxidation states list +6, +1 and +3 as the most stable.

7. In aqueous solutions, +3 is among the most stable oxidation states.

8. Tetrahalides of this element also show similarities in stability to iridium, making way for a possible +4 state.

The following table illustrates some known properties of Meitnerium.

Properties of Meitnerium

Activity: Ask your teacher for some more Mt periodic table properties as well as important pointers to know. Learn them and discuss them with friends. 

The element’s immensely high rate of decay and relativistic effects has made it almost impossible to produce in large amounts. Presently, it is only manufactured in sparse quantities for scientific research. 

Experimental Chemistry on Meitnerium

Very few elements are there in the periodic table which has so little chemical or physical properties known to us, and Meitnerium is one of them. Because of the very short-lived radioactive isotopes and other volatile compounds which decay into other atoms faster than needed to be experimented upon, Mt has extremely limited functions. Some of its chemical compounds which are sufficiently volatile include Meitnerium hexafluoride (MtF6) and another homologue of the same compound, iridium hexafluoride (IrF6). 

Though students may debate that the half-life of 278Mt is 4.5 seconds and that is enough to carry experiments on, another problem comes along with it. A steady scientific experiment expected to produce any tangible result needs a huge number of atoms of the same element. But till now, only ten atoms of Meitnerium have been produced at scale. Due to all these factors, Mt has not received the same research enthusiasm as had some of its other heavier counterparts like livermorium and copernicium.  

When seaborgium hexacarbonyl was successfully produced in 2014, there arrived a hope in the scientific sphere that formation of carbonyl compounds can be useful for studying such heavy elements. 

But due to similar reasons stated above, such studies were not possible for Mt, though 278Mt and 276Mt live long enough to perform experiments and can be produced from 294Ts and 288Mc. 

Another isotope, 270Mt, observed in the decay procedure of 278Nh, has a half-life of 0.69 seconds, which is again sufficient for experimentation. But even for that, a direct production procedure needs to be formulated, which has not yet been done.

So, this was all regarding Meitnerium and its chemical and physical properties. If you want to learn more about Meitnerium or its other heavier counterparts, visit Vedantu’s website or download our mobile app today. We host numerous such tutorials and guides on several topics related to your exams. See you there!