Superatom

Certain aluminum clusters have superatom properties. These aluminium clusters are generated as anions (Al⁻
_n with n = 1, 2, 3, … ) in helium gas and reacted with a gas containing iodine. When analyzed by mass spectrometry one main reaction product turns out to be Al
₁₃I⁻
.[2] These clusters of 13 aluminium atoms with an extra electron added do not appear to react with oxygen when it is introduced in the same gas stream, indicating a halide-like character and a magic number of 40 free electrons. Such a cluster is known as a superhalogen.[3][4][5][6] The cluster component in Al
₁₃I⁻
ion is similar to an iodide ion or better still a bromide ion. The related Al
₁₃I⁻
₂ cluster is expected to behave chemically like the triiodide ion.[2]

Similarly it has been noted that Al
₁₄ clusters with 42 electrons (2 more than the magic numbers) appear to exhibit the properties of an alkaline earth metal which typically adopt +2 valence states. This is only known to occur when there are at least 3 iodine atoms attached to an Al⁻
₁₄ cluster, Al
₁₄I⁻
₃. 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.[7][8]

It is particularly easy and reliable to study atomic clusters of inert gas atoms by computer simulation because interaction between two atoms can be approximated very well by the Lennard-Jones potential. Other methods are readily available and it has been established that the magic numbers are 13, 19, 23, 26, 29, 32, 34, 43, 46, 49, 55, etc.[9]

• Al
  ₇ = the property is similar to germanium atoms.
• Al
  ₁₃ = the property is similar to halogen atoms, more specifically, chlorine.
  • Al
    ₁₃I⁻
    _x, where x = 1–13.[10]
• Al
  ₁₄ = the property is similar to alkaline earth metals.
  • Al
    ₁₄I⁻
    _x, where x = 1–14.[10]
• Al
  ₂₃
• Al
  ₃₇
• Al
  ₅O⁻
  ₄ [11]

• Li(HF)₃Li = the (HF)₃ interior causes 2 valence electrons from the Li to orbit the entire molecule as if it were an atom's nucleus.[12]

• Li(NH₃)₄ = Has one diffuse electron orbiting around Li(NH₃)₄⁺ core, i.e., mimics an alkali-metal atom.[13][14]
• Be(NH₃)₄ = Has two diffuse electrons orbiting around Be(NH₃)₄²⁺ core, i.e., mimics He-atom.[15][16]

• VSi₁₆F = has ionic bonding.[17]
• A cluster of 13 platinum becomes highly paramagnetic, much more so than platinum itself.[18]
• A cluster of 2,000 rubidium atoms.[19]

Superatom complexes are a special group of superatoms that incorporate a metal core which is stabilized by organic ligands. In thiolate-protected gold cluster complexes a simple electron counting rule can be used to determine the total number of electrons (n_e) which correspond to a magic number via,

${\displaystyle n_{e}=N\nu _{A}-M-z}$

where N is the number of metal atoms (A) in the core, v is the atomic valence, M is the number of electron withdrawing ligands, and z is the overall charge on the complex.[20] For example the Au₁₀₂(p-MBA)₄₄ has 58 electrons and corresponds to a closed shell magic number.[21]

• Atom cluster
• Catenation
• Metal aromaticity
• Bose–Einstein condensate
• Quantum dot

• Designer Magnetic Superatoms, J.U. Reveles, et al. 2009
• Gold Superatom Complexes, M. Walter et al. 2008
• Gold Superatom Complexes P.D. Jadzinsky et al. 2007
• Multiple Valence Superatoms, J.U. Reveles, S.N. Khanna, P.J. Roach, and A.W. Castleman Jr., 2006
• On the Aluminum Cluster Superatoms acting as Halogens and Alkaline-earth Metals, Bergeron, Dennis E et al., 2006
• Clusters of Aluminum Atoms Found to Have Properties of Other Elements Reveal a New Form of Chemistry, innovations report, 2005. Have a picture of Al₁₄.
• Clusters of Aluminum Atoms Found to Have Properties of Other Elements Reveal a New Form of Chemistry, Penn State, Eberly College of Science, 2005
• Research Reveals Halogen Characteristics innovations report, 2004. Have pictures of Al₁₃.