Phonon band structure (supercell [3, 3, 3], Δ=0.01 Å); no imaginary modes; min freq = -0.08 THz
Cell + Ionic relaxation with Orb v3; 0.03 eV/Å threshold; final energy = -116.5822 eV; energy change = -0.0009 eV; symmetry: R-3m → R-3m
