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,^[2][3] synthesized,^[4] and experimentally confirmed^[5] to superconduct at near room-temperatures. It has a superconducting transition temperature T_C around 250 K (−23 °C; −10 °F) at a pressure of 150 gigapascals (22×10^⁶ psi), and its synthesis required pressures above approximately 160 gigapascals (23×10^⁶ psi).^[6][7]

Lanthanum decahydride

Identifiers
CAS Number	1130489-79-0[1]
3D model (JSmol)	Interactive image
InChI InChI=1S/La.10H Key: WKJDXOLLSPZSBN-UHFFFAOYSA-N
SMILES [LaH10]
Properties
Chemical formula	H10La
Molar mass	148.985 g·mol−1
Structure
Crystal structure	Cubic
Space group	Fm3m
Lattice constant	a = 5.1019(5) Å at 150 GPa
Lattice volume (V)	132.80(4) Å3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synopsis

Since its discovery in 2019,^[5] the superconducting properties of LaH₁₀ and other lanthanum-based superhydrides have been experimentally confirmed in multiple independent experiments.^{[8][9][10][11]} The compound exhibits a Meissner effect below the superconducting transition temperature.^[12] A cubic form can be synthesized at 1,000 K (730 °C; 1,340 °F),^[6] and a hexagonal crystal structure can be formed at room temperature.^[13] Further reports indicate T_c is increased with nitrogen doping,^[14] and decreased with the introduction of magnetic impurities.^[15]

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.^[16]

A similar compound, lanthanum boron octahydride, was computationally predicted to be a superconductor at 126 K (−147 °C; −233 °F) and pressure 50 gigapascals (7.3×10^⁶ psi).^[17]