Chemical templates that assemble the metal superhydrides*

The recent discoveries of metal superhydrides provide a new route to room-temperature superconductors. However, their structure trends and the chemical driving force needed to dissociate H₂ and form H covalent network cannot be explained by direct metal-hydrogen bonds. Here, we show that the understanding of superhydrides formation needs a perspective beyond the traditional chemical bonds. By analyzing high-throughput calculation results of metals across the periodic table and in various lattices, we show that, after removing H, the remaining metal lattices exhibit large electron occupations of the nonatomic interstitial orbitals, which matches excellently to H lattices and their wavefunctions like a template. Furthermore, H lattices consist of 3D aromatic building units that are greatly stabilized by chemical templates of metals near the s−d border. This theory can naturally explain the stability and structure trends of superhydrides and greatly enhance the efficiency of predicting new materials, such as two-metal superhydrides.