The core (inner) electrons do not directly impact chemical bond formation, which is a fundamental concept in the development of Effective Core Potential (ECP) Basis Sets . This approach uses an average potential profile to describe the core electrons, as detailing each electron individually is computationally expensive . LanL2DZ, an ECP basis set, was developed to reduce computational costs associated with metal-based structures and to account for relativistic effects in deep core electrons . Although LanL2DZ provides high accuracy for elements such as sodium (Na) and heavier atoms, it lacks polarization functions, which are crucial for accurately describing frontier orbitals, redox reactions, and electronic excitations. Also, some ECPs do not include diffuse functions necessary for effectively describing anions. Including d-type polarization functions can enhance the accuracy of the basis set. While there are several ECP basis sets avail-able, such as Def2TZVPP, Def2SVP, and SDD, the use of valence triple-ζ (triple zeta) functions can significantly increase computational costs . Thus, LanL2DZ remains a practical and efficient choice for investigating metallacage structures.