Crystal structure stability of several fluorite derivative oxides is often governed by the type of anion defects and defect complexes. Upon relaxation, these oxides result in structures whose order varies from very long-range to short-range ordering. It has been seen that small changes in stoichiometry result in tailoring these defect complexes, thus resulting in the modification of physical properties. Oxides with generic stoichiometry M7O12 occupy an intermediate place between fluorite and bixbyite structure types. Among the family of M7O12 compounds, A6UO12 are of interest because we believe that ternary oxides with this kind of formula are important to understand the compositional evolution of UO2 fuel and fission product stabilization during service in a light-water reactor, where lanthanide fission products are simultaneously incorporated into the fuel matrix and also, in the field of actinide waste forms. We will discuss the structural characteristics of the chemical bonds in La6UO12, and Y6UO12 and the implications of large dispersion in distances on the chemical bond characteristics. The characteristics of the chemical bonds were examined using atoms-in-molecule (AIM) Bader’s analysis method to provide estimates for the Bader charges of the individual atoms, as well as the locations of the bond critical points (BCPs) between bonding atoms, the charge densities at these BCPs, and the local curvature of the charge density. Density function theory (DFT) calculations were performed to obtain the electron charge densities for La6UO12, and Y6UO12.