To apply this equation, it is necessary to consider the combination of an anion-like (base-like) host for cationic intercalants and a cation-like (acid-like) host for anionic intercalants. Therefore, we classified the hosts according to the electronegativity of their constituent elements as follows: graphite in Figure (a) is classified as both acid-like and baselike, i.e., an amphoteric host; hosts in Figure , where the elements coordinating to the intercalant are highly electronegative, are classified as base-like hosts; hosts in Figure and, where the opposite configuration of Figures ) is observed, are classified as acid-like hosts. We then performed host-specific regressions for the 41 cation intercalants with 169 base-like hosts and 7 anion intercalants with 24 acidlike hosts, resulting in a total of 193 regressions using 7,097 data.