The P nma SG of the orthorhombic structure can transform to P 2 1 /c by reducing point group symmetry operations while retaining translational symmetry (t 2 ). This structure connects to the final C2/c SG structure, either directly or via P 1. Figure : The energy differences of vaterite-like structures sampled during the WTMetaD simulations and vaterite crystals from previous studies. The relative energies of calcite crystal are also plotted.