Cell + Ionic relaxation with Orb v3 conservative inf MPA; 0.03 eV/Å threshold; final energy = -29.3397 eV; energy change = -11.2402 eV; symmetry: Im-3m → P1
H3S in Im-3m symmetry at 250 GPa, from Belli, Zurek & Errea (npj Comput. Mater. 2026). SB class: QNEs suppress Tc (226 to 190 K).