  The recent discoveries of many metal superhydrides provide a new route to
room-temperature superconductors. However, their stability and structure trends
and the large chemical driving force needed to dissociate H2 molecules and form
H covalent network cannot be explained by direct metal-hydrogen bonds and
volume effect. Here, we demonstrate that the understanding of superhydrides
formation needs a perspective beyond traditional chemical bond theory. Using
high-throughput calculations, we show that, after removing H atoms, the
remaining metal lattices exhibit large electron localization at the
interstitial regions, which matches excellently to the H lattice like a
template. Furthermore, H lattices consist of 3D aromatic building units that
are greatly stabilized by chemical templates of metals close to s-d border. The
chemical template theory can naturally explain the stability and structure
trends of superhydrides and help to predict new materials such as two-metal
superhydrides.
