Metallic hydrogen

Metallic hydrogen is a phase of hydrogen that is theorized to occur under extremely high pressures. In this state, hydrogen molecules (H₂) are thought to dissociate into individual hydrogen atoms, which can then exhibit properties similar to metals, including electrical conductivity. This phenomenon is predicted to occur because at high pressures, the electron orbitals of hydrogen atoms overlap, allowing them to behave like a sea of delocalized electrons, similar to metals.