The researchers were able to synthesize a forbidden compound of cerium and hydrogen (CeH9), which demonstrates superconductivity at low pressures. (Image credit: MIPT)


Researchers from the US, Russia, and China have seemingly done the impossible by synthesizing a ‘forbidden,’ or ‘impossible’ compound, known as cerium superhydride (CeH9), that exhibits superconductivity at low pressure. Superconductors are capable of conducting an electrical current with little to no energy bleed or resistance, making them perfect for electromagnets, particle accelerators, MRI machines, maglev trains, or theoretically, even power lines.


That said, superconductors are not a perfect material, and do have their downsides, including only being able to functions at low temperatures (-1380C, current record stands at -130C), and at super-high pressures of almost 2-million atmospheres. To put that into perspective, German U-Boats from WWII had a crush depth of around 200 to 300-meters or roughly 20 to 30-atmospheres.


Cerium superhydride was created by placing a microscopic sample of metal cerium into a diamond anvil, along with another chemical that releases hydrogen when heated, and as pressure grows, the new compound is created. (Image credit: MIPT)


To create cerium superhydride, the engineers placed a microscopic sample of metal cerium into a diamond anvil cell, along with another chemical that releases hydrogen when laser-heated. The cerium sample is squeezed between a pair of diamonds to create the 1-million-atmosphere pressure needed for the chemical reaction to occur, and as more pressure is introduced, greater proportions of hydrogen grew in the reactor.


The researchers then used X-ray diffraction to discern the position of cerium atoms after the reaction and found they had synthesized cerium superhydride in a crystal lattice, which is comprised of cages of 29 hydrogen atoms in a near-spherical formation. The particles in each cage are held together through covalent bonds with a cavity that contains a single cerium atom. With the breakthrough notwithstanding, the researchers want to add a third element to the mix- a triple cocktail of hydrogen and two metals, and then implement AI to see what promising candidates make an even better superconductor. 


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