Inert gas helium, famous for its reluctance to react with other elements, has produced a very stable new compound called sodium helide. This feat was achieved by subjecting helium to high pressure to react with sodium in high temperature.
The structure of the resulting compound had strong bonds, a far cry from the usual weak bonds of some helium compounds.
Properties Not Known
Explaining the behavior of helium at high pressure was Alex Boldyrev, Utah State University professor.
"That's because of extremely high pressure, like that found at the Earth's core or giant neighbors, completely alters helium's chemistry," Boldyrev said.
Boldyrev and his doctoral student Ivan Popov were part of an international team of researchers, led by Artem Oganov of Stony Brook University, who conducted the research on helium.
They have published the findings in Nature Chemistry.
However, the new compound's properties have not been fully understood with practical applications yet be charted out as scientists have created only small amounts of the compound, according to Alexander Goncharov, a physicist from Carnegie Institution for Science in Washington, D.C, and the co-author.
However, the new compound will be a stepping stone for researchers to produce new weird materials in lower pressures.
Efforts to make compounds with helium started in the 1960s despite its reluctance. As a least reactive element, helium was deemed incapable of forming chemical compounds at all. Though xenon compounds were created with helium, they were all short lived.
How Was It Done?
Before planning the reaction of helium with sodium, scientists led by Artem Oganov of Stony Brook University in New York made the necessary computer calculations to confirm what all compounds are possible with helium.
The analysis showed sodium can work with helium if it can be squeezed under high pressure.
In the experiments, Goncharov and colleagues mixed small amounts of helium and sodium between a pair of diamonds and scaled up pressures million times the atmospheric pressure of Earth.
Thereafter the material was heated with lasers to temperatures above 1200° Celsius.
The resulting X-rays gave an idea of the compound's structure that matched the computer predictions.
The unusual compound is an electride, and defying its bizarre nature, sodium helide behaved like a commonplace compound where chloride ions are negatively charged. While the isolated electron pairs act like negative ions, the eight sodium atoms enveloping each helium atom will be acting as positive ions.
In the computer calculations, the possibility of forming a compound of helium, sodium and oxygen, called Na2HeO, at lower pressures was also predicted possible.
India Eyes Moon's Helium
Meanwhile, a scientist with India's space agency ISRO has said India is looking to meet its entire energy needs by mining lunar dust from the moon in the next two decades.
Sivathanu Pillai, the distinguished professor with ISRO, and former head of BrahMos Aerospace program, said the bulk of India's energy requirements could be met by mining helium-3 from the moon. The space agency has accorded top priority to the program.
"By 2030, this process target will be met," Pillai told the ORF-Kalpana Chawla Space Policy Dialogue held by think tank group Observer Research Foundation.
The expert noted that lunar dust is rich in helium-3 and added that not only India but many other countries are also working on such projects as the moon has enough helium to meet the energy needs of the world.
The European Space Agency is also on record as it is believed "this isotope could provide safer nuclear energy in a fusion reactor since it is not radioactive and would not produce dangerous waste products."
