  Achieving superconductivity at room temperature (RT) is a holy grail in
physics. Recent discoveries on high-Tc superconductivity in binary hydrides H3S
and LaH10 at high pressure have directed the search for RT superconductors to
compress hydrides with conventional electron-phonon mechanisms. Here, we
predict an exceptional family of superhydrides under high pressures, MH12 (M =
Mg, Sc, Zr, Hf, Lu), all exhibiting RT superconductivity with calculated Tcs
ranging from 313 to 398 K. In contrast to H3S and LaH10, the hydrogen
sublattice in MH12 is arranged as quasi-atomic H2 units. This unique
configuration is closely associated with high Tc, attributed to the high
electronic density of states derived from H2 antibonding states at the Fermi
level and the strong electron-phonon coupling related to the bending vibration
of H2 and H-M-H. Notably, MgH12 and ScH12 remain dynamically stable even at
pressure below 100 GPa. Our findings offer crucial insights into achieving RT
superconductivity and pave the way for innovative directions in experimental
research.
