Relaxed with Orb v3; 0.03 eV/Å threshold; final energy = -168.0808 eV; energy change = -0.0111 eV; symmetry: P4/mbm → P4/mbm
Phonon band structure (supercell [2, 2, 2], Δ=0.01 Å); imaginary modes detected; min freq = -8.23 THz