Intercalation of alkali metals

Except for sensor applications, the intercalation of alkali metal ions in metal hexacyanoferrates was used for adsorption and separation of cesium ions from different aqueous solutions with Prussian blue [43,44] and cupric hexacyanoferrate [45,46],... 

Intercalation of alkali-metal atoms into zirconium disulphide has been reviewed.254 Only alternate layers of vacant sites are occupied by alkali-metal atoms when ZrS2 is treated with a dilute solution of alkali metal in liquid ammonia.255 At higher con-... 

As mentioned earlier, intercalation of alkali metals in host solids in readily accomplished electrochemi-cally. It is easy to see how both intercalation (reduction of the host) and deintercalation (oxidation of the host) are processes suited for this method. Thus, lithium intercalation is carried out using a lithium anode and a lithium salt in a non-aqueous solvent... 

The pore model is unable to describe this late reactivity maximum around X=0.7 as it foresees a possible maximum reactivity to occur only between 0 X < 0.393. In the literature, the late occurrence has been explained by intercalation of alkali metal species into the carbon stmeture, leading to a gradual release of active centres with conversion. We note, however, that intercalation effects have seldom been reported for charcoals (in contrast to graphite). In our opinion the cause for the "anomalous" reactivity behaviour stems from a combination of structural and catalytic phenomena emerging from the reaction mechanism involved. The most important mechanism proposed nowadays is the oxygen transfer mechanism in which the oxygen is extracted from the reactant gas (CO2) by the catalyst, which then supplies it in an active form to the carbon. 

Intercalation of Alkali-Metal Hydrides into Graphite. 

In general intercalation compounds often show interesting properties as electronic conductors. That is also the case of the products of the intercalation of alkali metals in buckminsterfullerene. As discussed above, this process results in an electron transfer from guest to host thus giving rise to fulleride anions. Such a charge transfer is fundamentally due to the large electron affinity and low reduction potential that characterize the fullerenes. 

Thus, the electronic structures of fullerene anionic species can be obtained by filling the 3-fold degenerate LUMOs of the cluster. Accordingly, the products of the intercalation of alkali metals in fullerenes are expected to show, depending on the intercalation degree, an enhanced conductivity. In some cases superconductivity has been also observed (vide infra). 

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