Following structural generation, each molecule is optimized at the B3LYP/6-31G(2df,p) level theory with Gaussian 09 software, which ensures chemical validity and stability. However, complexities may lead to convergence failures or unstable configurations. To mitigate this, a filtering mechanism akin to QM9 is enacted, setting a maximum optimization cycle limit of 200 and implementing stricter convergence criteria. Ultimately, only structures exhibiting successful optimization and positive vibrational frequencies, indicative of stability, are retained in the final QM-sym database, striking a balance between symmetry incorporation and molecular stability.