Superatom Explained

In chemistry, a superatom is any cluster of atoms that seem to exhibit some of the properties of elemental atoms.^[1]

Sodium atoms, when cooled from vapor, naturally condense into clusters, preferentially containing a magic number of atoms (2, 8, 20, 40, 58, etc.), with the outermost electron of each atom entering an orbital encompassing all the atoms in the cluster. Superatoms tend to behave chemically in a way that will allow them to have a closed shell of electrons, in this new counting scheme.

Aluminum clusters

Certain aluminum clusters have superatom properties. These aluminium clusters are generated as anions (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 .^[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 ion is similar to an iodide ion or better still a bromide ion. The related cluster is expected to behave chemically like the triiodide ion.^[2]

Similarly it has been noted that 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 cluster, . 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]

• = the property is similar to germanium atoms.
• = the property is similar to halogen atoms, more specifically, chlorine.
  • , where .^[10]
• = the property is similar to alkaline earth metals.
  • , where .^[10]
    • ^[11]

Other clusters

• = the interior causes 2 valence electrons from the Li to orbit the entire molecule as if it were an atom's nucleus.^[12]
• = Has one diffuse electron orbiting around core, i.e., mimics an alkali-metal atom.^{[13] [14]}
• = Has two diffuse electrons orbiting around core, i.e., mimics He-atom.^{[15] [14]}
• = has ionic bonding.^[16]
• A cluster of 13 platinum atoms becomes highly paramagnetic, much more so than platinum itself.^[17]
• A cluster of 2,000 rubidium atoms.^[18]

Superatom complexes

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 which correspond to a magic number via,

n _{e} = N\nu _{A} - M - z

where is the number of metal atoms (A) in the core, is the atomic valence, is the number of electron withdrawing ligands, and is the overall charge on the complex.^[19] For example the Au₁₀₂(p-MBA)₄₄ has 58 electrons and corresponds to a closed shell magic number.^[20]

Gold superatom complexes

• ^[21]
  • ^[22]

Other superatom complexes

• ^[23]
• ^[24]
• – In 2018 researchers produced 15-nm-thick flakes of this superatomic material. They anticipate that a monolayer will be a superatomic 2-D semiconductor and offer new 2-D materials with unusual, tunable properties.^[25]
• Organo− Zintl-based superatoms:[{{chem2|Ge9(CHO)3}}] and [{{chem2|Ge9(CHO)}}]^[26]

See also

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

External links

• 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.

Notes and References

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2. Bergeron . D. E. . Formation of : Evidence for the Superhalogen Character of Al13 . . American Association for the Advancement of Science (AAAS) . 304 . 5667 . 2 April 2004 . 0036-8075 . 10.1126/science.1093902 . 15066775 . 84–87. 26728239 .
3. Reddy. G. Naaresh. Parida. Rakesh. Giri. Santanab. 2017-12-12. Functionalized deltahedral Zintl complexes Ge9R3 (R = CF3, CN, and NO2): a new class of superhalogens. Chemical Communications. en. 53. 99. 13229–13232. 10.1039/C7CC08120K. 29182179. 1364-548X.
4. Giri. Santanab. Child. Brandon Z.. Jena. Puru. 2014. Organic Superhalogens. ChemPhysChem. en. 15. 14. 2903–2908. 10.1002/cphc.201402472. 25056518. 1439-7641.
5. Reddy. Gorre Naaresh. Giri. Santanab. 2016-05-10. Super/hyperhalogen aromatic heterocyclic compounds. RSC Advances. en. 6. 52. 47145–47150. 10.1039/C6RA08625J. 2016RSCAd...647145R. 2046-2069.
6. Sinha . Swapan . Jena . Puru . Giri . Santanab . 2022-08-12 . Functionalized nona-silicide [Si9R3] Zintl clusters: a new class of superhalogens ]. Physical Chemistry Chemical Physics . 24 . 35 . 21105–21111 . en . 10.1039/D2CP02619H . 36018293 . 2022PCCP...2421105S . 1978872 . 251551751 . 1463-9084.
7. Philip Ball, "A New Kind of Alchemy", New Scientist Issue dated 2005-04-16.
8. Bergeron . D. E. . Al Cluster Superatoms as Halogens in Polyhalides and as Alkaline Earths in Iodide Salts . . American Association for the Advancement of Science (AAAS) . 307 . 5707 . 14 January 2005 . 0036-8075 . 10.1126/science.1105820 . 231–235. 15653497 . 2005Sci...307..231B . 8003390 .
9. Harris . I. A. . Kidwell . R. S. . Northby . J. A. . Structure of Charged Argon Clusters Formed in a Free Jet Expansion . Physical Review Letters . American Physical Society (APS) . 53 . 25 . 17 December 1984 . 0031-9007 . 10.1103/physrevlett.53.2390 . 2390–2393. 1984PhRvL..53.2390H . 13793440 .
10. http://etd.vcu.edu/theses/available/etd-01102007-131059/unrestricted/jonesno_phd.pdf Naiche Owen Jones, 2006.
11. Al5O4 Superatom with Potential for New Materials Design . 2008. 10.1021/ct800232b. Das. Ujjal. Raghavachari. Krishnan. Journal of Chemical Theory and Computation. 4. 12. 2011–2019. 26620474.
12. Sun . Xiao-Ying . Li . Zhi-Ru . Wu . Di . Sun . Chia-Chung . Extraordinary superatom containing double shell nucleus: Li(HF)₃Li connected mainly by intermolecular interactions . International Journal of Quantum Chemistry . Wiley . 107 . 5 . 2007 . 0020-7608 . 10.1002/qua.21246 . 1215–1222. 2007IJQC..107.1215S .
13. Ariyarathna. Isuru R.. Pawłowski. Filip. Ortiz. Joseph Vincent. Miliordos. Evangelos. 2018. Molecules mimicking atoms: monomers and dimers of alkali metal solvated electron precursors. Physical Chemistry Chemical Physics. en. 20. 37. 24186–24191. 10.1039/C8CP05497E. 30209476. 2018PCCP...2024186A. 1463-9076.
14. Ariyarathna. Isuru. 2021-03-01. First Principle Studies on Ground and Excited Electronic States: Chemical Bonding in Main-Group Molecules, Molecular Systems with Diffuse Electrons, and Water Activation using Transition Metal Monoxides. PhD. en.
15. Ariyarathna. Isuru R.. Khan. Shahriar N.. Pawłowski. Filip. Ortiz. Joseph Vincent. Miliordos. Evangelos. 2018-01-04. Aufbau Rules for Solvated Electron Precursors: Be(NH 3) 4 2+ Complexes and Beyond. The Journal of Physical Chemistry Letters. en. 9. 1. 84–88. 10.1021/acs.jpclett.7b03000. 29232138. 1948-7185. free.
16. Koyasu . Kiichirou . Atobe . Junko . Akutsu . Minoru . Mitsui . Masaaki . Nakajima . Atsushi . Electronic and Geometric Stabilities of Clusters with Transition Metal Encapsulated by Silicon . The Journal of Physical Chemistry A . American Chemical Society (ACS) . 111 . 1 . 2007 . 1089-5639 . 10.1021/jp066757f . 42–49. 17201386. 2007JPCA..111...42K.
17. http://nanotechweb.org/cws/article/tech/26782 Platinum nanoclusters go magnetic
18. https://www.nist.gov/public_affairs/gallery/95subose.htm Ultra Cold Trap Yields Superatom
19. Walter . M. . Akola . J. . Lopez-Acevedo . O. . Jadzinsky . P. D. . Calero . G. . Ackerson . C. J. . Whetten . R. L. . Gronbeck . H. . Hakkinen . H. . A unified view of ligand-protected gold clusters as superatom complexes . Proceedings of the National Academy of Sciences . 105 . 27 . 1 June 2008 . 0027-8424 . 10.1073/pnas.0801001105 . 9157–9162. 18599443 . 2442568 . 2008PNAS..105.9157W . free.
20. Jadzinsky . P. D. . Calero . G. . Ackerson . C. J. . Bushnell . D. A. . Kornberg . R. D. . Structure of a Thiol Monolayer-Protected Gold Nanoparticle at 1.1 Å Resolution . Science . American Association for the Advancement of Science (AAAS) . 318 . 5849 . 19 October 2007 . 0036-8075 . 10.1126/science.1148624 . 17947577 . 430–433. 2007Sci...318..430J . 1566019 .
21. Akola . Jaakko . Walter . Michael . Whetten . Robert L. . Häkkinen . Hannu . Grönbeck . Henrik . On the Structure of Thiolate-Protected Au₂₅ . Journal of the American Chemical Society . American Chemical Society (ACS) . 130 . 12 . 2008 . 0002-7863 . 10.1021/ja800594p . 18321117 . 3756–3757.
22. Lopez-Acevedo . Olga . Akola . Jaakko . Whetten . Robert L. . Grönbeck . Henrik . Häkkinen . Hannu . Structure and Bonding in the Ubiquitous Icosahedral Metallic Gold Cluster Au₁₄₄(SR)₆₀ . The Journal of Physical Chemistry C . American Chemical Society (ACS) . 113 . 13 . 16 January 2009 . 1932-7447 . 10.1021/jp8115098 . 5035–5038.
23. Hartig . Jens . Stößer . Anna . Hauser . Petra . Schnöckel . Hansgeorg . A Metalloid Ga₂₃₁₁ Cluster: The Jellium Model Put to Test . Angewandte Chemie International Edition . Wiley . 46 . 10 . 26 February 2007 . 1433-7851 . 10.1002/anie.200604311 . 17230594 . 1658–1662.
24. Clayborne . Peneé A. . Lopez-Acevedo . Olga . Whetten . Robert L. . Grönbeck . Henrik . Häkkinen . Hannu . The Al₅₀Cp*₁₂ Cluster – A 138-Electron Closed Shell (L = 6) Superatom . European Journal of Inorganic Chemistry . Wiley . 2011 . 17 . 13 May 2011 . 1434-1948 . 10.1002/ejic.201100374 . 2649–2652.
25. News: Researchers create first superatomic 2-D semiconductor. Zyga. Lisa. Phys.org. 2018-02-18.
26. 2017-10-16. Organo−Zintl-based superatoms: [Ge9(CHO)3] and [Ge9(CHO)]. Chemical Physics Letters. en. 686. 195–202. 10.1016/j.cplett.2017.08.056. 0009-2614. Reddy. G. Naaresh. Jena. Puru. Giri. Santanab. 2017CPL...686..195R. free.