Considering the Cs2AgBiCl6, we specifically investigate a chloride vacancy on the (Ag0.5Bi0.5)Cl2-terminated surface. The vacancy was stable in the positive charge state (+1), and its presence did not significantly alter the lattice structure of Cs2AgBiCl6. Upon addition of electrons, we observe the formation of an Ag-Bi dimer. In the neutral state, the dimer shows a distance of 2.82 Å, while in the negatively charged state the distance is reduced to 2.75 Å,