A researcher from IIT Roorkee was recently part of an international team that studied one of the heaviest man-made elements, a matter of pride for the Indian science community. Professor Moumita Maiti of IIT Roorkee studied 'Flerovium', one of the heaviest man-made so far, and an element which lasts for only a second.
Flerovium is the 114th element of the Periodic Table, and only a few atoms of the element can be produced in a nuclear accelerator. Flerovium atoms were produced in a nuclear accelerator in Germany. In order to produce a few Flerovium atoms every day, one needs to accelerate four trillion charged calcium atoms or calcium ions to the speed of light, and fire them at a plutonium target. The study describing the findings was recently published in the peer-reviewed journal Frontiers in Chemistry.
What is Flerovium? What was the aim of the study?
One of the main aims of the study was to find out if Flerovium is a heavy metal or a noble gas. The international team included researchers from Germany, the United States, Sweden, Japan, India, Australia, Finland, Poland and Norway.
There were only 83 elements in the periodic table until the middle of the 20th century. At that time, the periodic table started with hydrogen and ended with uranium, a radioactive element. Since then, researchers have discovered heavier elements, many of which are radioactive and not very long-lasting. Of these heavier elements, many are man-made through nuclear reactions.
Flerovium is one of the latest man-made elements. The 114th element in the current periodic table, Flerovium was first created in 1998 by scientists in Russia by hitting plutonium atoms with calcium atoms in a nuclear accelerator.
The international team, of which Professor Maiti is a part, along with Dr Susanta Lahiri from Saha Institute of Nuclear Physics, Kolkata, is studying Flerovium.
In a statement released by IIT Roorkee, Professor Maiti said that when scientists discover an element, they characterise it based on chemical tests but experimentation is extremely challenging for elements such as Flerovium because they are produced in a small number in a nuclear accelerator, and have a very short life. Researchers guess the chemical properties of unstable and elusive elements from where they are present in the periodic table, and from the number of proteins and electrons they have.
For instance, Flerovium is placed below lead in the periodic table, because of which one can expect it to be metallic. However, elements like Flerovium, which have too many protons in the nucleus, are likely to behave like noble gases such as radon and argon, relativity studies predict. Noble gases, also known inert gases, belong to Group 18 of the periodic table.
How was the study conducted?
Dr Maiti explained that since Flerovium atoms exist for only one second before decomposing, researchers must test them in less than a second. The Flerovium atoms bouncing off the plutonium target were transferred into a nuclear reactor within a tenth of a second. Inside the nuclear reactor, the Flerovium atoms were first brought in contact with silica, and then with gold, at progressively decreasing temperatures. The temperatures were reduced to as low as minus 160 degrees Celsius.
What did the study find?
Researchers had expected Flerovium to react with silica because it lies below lead. However it was found to be similar to mercury, as it reacted with gold. Had Flerovium been similar to noble gases, it would not have reacted with either silica or gold.
Only a few atoms of Flerovium were found to bind with the gold surface. This proves that Flerovium may demonstrate mercury-like behaviour. Meanwhile, other Flerovium atoms did not bind with gold anywhere on the surface, even when the lowest temperature was reached.
Since not all Flerovium atoms were absorbed in gold, it proves that the heavy element is less reactive than mercury. Also, the fact that a few Flerovium atoms reacted with gold shows that the heavy element is not as inert as noble gases.
Significance of the study
It is important to understand the nature of extremely heavy elements in order to know more about concepts such as 'island of stability'. This refers to the superior stability of some elements over others. If researchers understand the properties of superheavy elements, they will know why only a few such elements exist in nature.
The study helped the team gain scientific understanding of new elements of the periodic table and is believed to encourage young Indian researchers to explore complex challenges.