Information AboutSuperatoms |
| CATEGORIES ABOUT SUPERATOM | |
| atomic physics | |
| cluster chemistry | |
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Sodium atoms when left to condense in clusters from Vapour naturally form into clusters of 8, 20, 40, 58 or 92 atoms (the Magic Numbers ). The first of these can be recognised as the number of electrons in filled s and p Orbitals . The suggestion is that free electrons in the cluster form atomic like structure (larger numbers show deviations from the number of electrons in a shell as the potential is not central). The atomic properties of this structure should mimic the atomic properties of atoms with filled s and p orbitals, ''i.e.'' the Noble Gases . Certain Aluminium Cluster s have superatom properties. These aluminium clusters are generated as Anions (Aln- with n = 1,2,3...) in a Helium gas and reacted with a gas containing molecular iodine. When analyzed by Mass Spectroscopy one main reaction product turns out to be Al13I- . These clusters of 13 Aluminium atoms with an extra electron added does also appear not to react with Oxygen when it is introduced in the same gas stream. Assuming each atom liberates its 3 valence electrons, this means that there are 40 electrons present, which is one of the Magic Number s noted above for sodium, and implies that these numbers are a reflection of the Noble Gases . Calculations show that the additional electron is located in the aluminium cluster at the location directly opposite from the iodine atom. The cluster must therefore have a higher Electron Affinity for the electron than iodine and therefore the aluminium cluster is called a superhalogen. The cluster component in Al13I- ion is similar to an Iodine ion or better still a Bromine atom. The related Al13I2- cluster is expected to behave chemically like the Triiodide ion Similarly it has been noted that Al14 clusters with 42 electrons (2 more than the magic numbers) appear to exhibit the properties of an Alkali Metal which typically adopt +2 Valence states. This is only known to occur when there are at least 3 iodine atoms attached to an Al14- cluster, Al14I3-. The Anionic cluster has a total of 43 Itinerant electrons, but the three Iodine atoms each remove one of the Itinerant electrons to leave 40 electrons in the Jellium shell. . SEE ALSO REFERENCES |
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