Lanthanum decahydride

Lanthanum decahydride is a polyhydride or superhydride compound of lanthanum 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 TC around 250 K at a pressure of 150 GPa, and its synthesis required pressures above approximately 160 GPa.

Synopsis
Since its discovery in 2019, the superconducting properties of LaH10 and other lanthanum-based superhydrides have been experimentally confirmed in multiple independent experiments. The compound exhibits a Meissner effect below the superconducting transition temperature. A cubic form can be synthesized at 1000 K, and a hexagonal crystal structure can be formed at room temperature. Further reports indicate Tc is increased with nitrogen 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.

A similar compound, lanthanum boron octahydride, was computationally predicted to be a superconductor at 126 K and pressure 50 GPa.