Lanthanum decahydride
Lanthanum decahydride is a polyhydride or superhydride compound of lanthanum and hydrogen that shows promise of being a high-temperature superconductor. It has a superconducting transition temperature TC ~ at a pressure of 150 gigapascals, which is a record high as of 2019, and its synthesis required pressures above ~160 GPa. A cubic form can be synthezised at, and a hexagonal crystal structure can be formed at room temperature.
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.