Seven types of structures and compositions were selected as hosts, C, AX2, A2X2, and A2Z, and their crystal structures are shown in Figure , where A represents all elements except lanthanides and actinides, X represents elements in groups 13 to 17, and Z represents C or N. In order to perform accurate regression, stable convergence of energy and structure calculations is required for various layered intercalation compounds. However, the interlayer compounds containing lanthanides and actinides have poor convergence in the calculations and are an obstacle to creating a high-quality database, thus they had to be excluded in this study. Figure (a) shows Graphite, the host of typical layered intercalation compounds, GICs, and the five crystal structures of GICs experimentally reported to date are shown in Figure . Figures ) and (c) show the structures with composition AX2, with an octahedral structure and a triangular prismatic structure, respectively. Figures ~ (f) represent structures with the composition A2X2 (relative to the composition of the intercalant, 1). Figures , (e) and (f) are rock-salt, anti-PbO and PbO structures, respectively. The difference between Figures ) and (f) is whether the outer layer of the two constituent elements is anionic or cationic, and in this study, the distinction is made by the electronegativity (Allred-Rochow's scale) of the two elements. Figure shows the crystal structures of these host compounds, respectively. Figure (g) shows a layered material with a composition of ZA2 (Z = C or N) with an octahedral structure. This crystal structure can be regarded as a termination-free structure of a substance called MXene. The intercalated crystal structures of this host are shown in Figure , known as the MAX phase. As intercalants, the elements colored in Figure were selected. These elements were chosen based on the availability of standard Gibbs free energy of ion formation and effective ionic radius data extracted from the references, excluding lanthanides and actinides for the same reason mentioned above. Elements in blue are more likely to become cations when hydrated, while those in red are more likely to become anions.