Lanthanum decahydride is a

polyhydride A polyhydride or superhydride is a compound that contains an abnormally large amount of hydrogen. This can be described as high hydrogen stoichiometry. Examples include iron pentahydride , , and . By contrast, the more well known lithium hydride o ...

or superhydride compound of

lanthanum Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements bet ...

and hydrogen (LaH₁₀) that has shown evidence of being a high-temperature superconductor. It was the first metal superhydride to be theoretically predicted, synthesized, and experimentally confirmed to superconduct at near room-temperatures. It has a superconducting transition temperature T_C around at a pressure of , and its synthesis required pressures above approximately .

Synopsis

Since its discovery in 2019, the superconducting properties of LaH₁₀ and other

-based superhydrides have been experimentally confirmed in multiple independent experiments. The compound exhibits a

Meissner effect In condensed-matter physics, the Meissner effect (or Meißner–Ochsenfeld effect) is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state when it is cooled below the critical temperature. Th ...

below the superconducting transition temperature. A cubic form can be synthesized at , and a hexagonal crystal structure can be formed at room temperature. Further reports indicate T_c is increased with

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

doping, and decreased with the introduction of magnetic impurities. The cubic form has each lanthanum atom surrounded by 32 hydrogen atoms, which form the vertices of an 18-faced shape called a

chamfered cube In geometry, a chamfer or edge-truncation is a topological operator that modifies one polyhedron into another. It separates the Face (geometry), faces by reducing them, and adds a new face between each two adjacent faces (moving the vertices ...

. A similar compound,

lanthanum boron octahydride Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements betw ...

, was computationally predicted to be a superconductor at and pressure .

References

{{Hydrides by group Lanthanum compounds High-temperature superconductors Metal hydrides