Tetraoxygen

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The tetraoxygen molecule (O4), also called oxozone, is an allotrope of oxygen consisting of four oxygen atoms.

Contents

History

Tetraoxygen was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law. [1] Though not entirely inaccurate, computer simulations indicate that although there are no stable O4 molecules in liquid oxygen, O2 molecules do tend to associate in pairs with antiparallel spins, forming transient O4 units. [2] In 1999, researchers thought that solid oxygen in its ε-phase, also known as red oxygen, (at pressures above 10 GPa) was O4. [3] However, in 2006, it was shown by X-ray crystallography that this stable phase is in fact octaoxygen (O
8). [4] Nevertheless, positively charged tetraoxygen has been detected as a short-lived chemical species in mass spectrometry experiments. [5]

Structure

Theoretical calculations have predicted the existence of metastable O4 molecules with two different shapes: a "puckered" square like cyclobutane or S4, [6] and a "pinwheel" with three oxygen atoms surrounding a central one in a trigonal planar formation similar to boron trifluoride or sulfur trioxide. [7] [8] It was previously pointed out that the "pinwheel" O4 molecule should be the natural continuation of the isoelectronic series BO3−
3, CO2−
3, NO−
3, [9] and analogous to SO3; that observation served as the basis for the mentioned theoretical calculations.

Theoretical structures of metastable O4.
Tetraoxygen-D2d-3D-balls.png Tetraoxygen-D3h-3D-balls.png
D2d structureD3h structure

In 2001, a team at the University of Rome La Sapienza conducted a neutralization-reionization mass spectrometry experiment to investigate the structure of free O4 molecules. [5] Their results did not agree with either of the two proposed molecular structures, but they did agree with a complex between two O2 molecules, one in the ground state and the other in a specific excited state.

Atmospheric occurrence

In atmospheric sciences, O4 usually refers to the collision-induced complex arising from interactions between two O2 molecules. Also called O2-O2 dimers, these unstable dimers exhibit distinct collision-induced absorption (CIA) bands in the UV and visible ranges. [10] Because molecular oxygen is well-mixed and the distribution is well known, the concentration of O2-O2 dimers is predictable and primarily dependent on air density. Since clouds change how light passes through the atmosphere, the strength of the O2-O2 absorption can be used to detect their presence and height. [11] [12] Therefore, satellite measurements of spectral radiance within the O2-O2 absorption bands can be used to calculate cloud properties such as cloud-top pressure and cloud fraction globally. [11] [12] The same absorption features, including bands at 360, 477 and 577 nm, are used to derive aerosol profiles in atmospheric optical spectroscopy, where the predictable distribution of O2 provides useful constraint in aerosol inversion techniques and radiative transfer models. [13]

Potential use

Tetraoxygen has been speculated as an alternative to traditional liquid oxygen in rocket propulsion. Its higher density—approximately twice that of liquid oxygen—could allow for smaller oxidizer tanks, lowering overall vehicle mass and increasing payload capacity. [14]

See also

References

  1. ↑ Lewis, Gilbert N. (1924). "The Magnetism of Oxygen and the Molecule O4". Journal of the American Chemical Society. 46 (9): 2027–2032. doi:10.1021/ja01674a008.
  2. ↑ Oda, Tatsuki; Alfredo Pasquarello (2004). "Noncollinear magnetism in liquid oxygen: A first-principles molecular dynamics study". Physical Review B. 70 (134402): 1–19. Bibcode:2004PhRvB..70m4402O. doi:10.1103/PhysRevB.70.134402. hdl: 2297/3462 . S2CID   123535786.
  3. ↑ Gorelli, Federico A.; Lorenzo Ulivi; Mario Santoro; Roberto Bini (1999). "The ε Phase of Solid Oxygen: Evidence of an O4 Molecule Lattice". Physical Review Letters. 83 (20): 4093–4096. Bibcode:1999PhRvL..83.4093G. doi:10.1103/PhysRevLett.83.4093.
  4. ↑ Lars F. Lundegaard, Gunnar Weck, Malcolm I. McMahon, Serge Desgreniers and Paul Loubeyre (2006). "Observation of an O8 molecular lattice in the phase of solid oxygen". Nature. 443 (7108): 201–204. Bibcode:2006Natur.443..201L. doi:10.1038/nature05174. PMID   16971946. S2CID   4384225.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. 1 2 Cacace, Fulvio; Giulia de Petris; Anna Troiani (2001). "Experimental Detection of Tetraoxygen". Angewandte Chemie International Edition. 40 (21): 4062–4065. doi:10.1002/1521-3773(20011105)40:21<4062::AID-ANIE4062>3.0.CO;2-X. PMID   12404493.
  6. ↑ Hernández-Lamoneda, R.; A. Ramírez-Solís (2000). "Reactivity and electronic states of O4 along minimum energy paths". Journal of Chemical Physics. 113 (10): 4139–4145. Bibcode:2000JChPh.113.4139H. doi:10.1063/1.1288370.
  7. ↑ Røeggen, I.; E. Wisløff Nilssen (1989). "Prediction of a metastable D3h form of tetra oxygen". Chemical Physics Letters. 157 (5): 409–414. Bibcode:1989CPL...157..409R. doi:10.1016/0009-2614(89)87272-0.
  8. ↑ Hotokka, M. (1989). "Ab initio study of bonding trends in the series BO33−, CO32−, NO3− and O4(D3h)". Chemical Physics Letters. 157 (5): 415–418. Bibcode:1989CPL...157..415H. doi:10.1016/0009-2614(89)87273-2.
  9. ↑ Jubert,A.H.; E.L.Varetti (1986). "On the possible existence of the O4 molecule with D3h symmetry". Anales de Química (Spain)82:227-230.
  10. ↑ Wagner, T.; von Friedeburg, C.; Wenig, M.; Otten, C.; Platt, U. (2002). "UV-visible observations of atmospheric O4 absorptions using direct moonlight and zenith-scattered sunlight for clear-sky and cloudy sky conditions". Journal of Geophysical Research: Atmospheres. 107 (D20): AAC 3–1–AAC 3-15. doi:10.1029/2001JD001026. ISSN   2156-2202.
  11. 1 2 Acarreta, J. R.; De Haan, J. F.; Stammes, P. (2004-03-16). "Cloud pressure retrieval using the O 2 ‐O 2 absorption band at 477 nm". Journal of Geophysical Research: Atmospheres. 109 (D5). doi:10.1029/2003JD003915. ISSN   0148-0227.
  12. 1 2 Choi, Haklim; Liu, Xiong; Gonzalez Abad, Gonzalo; Seo, Jongjin; Lee, Kwang-Mog; Kim, Jhoon (2021-01-05). "A Fast Retrieval of Cloud Parameters Using a Triplet of Wavelengths of Oxygen Dimer Band around 477 nm". Remote Sensing. 13 (1): 152. doi:10.3390/rs13010152. ISSN   2072-4292.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  13. ↑ Friess, U. and Monks, P. S. and Remedios, J. J. and Wagner, T. and Platt, U. (2005). "MAX-DOAS O4 measurements: A new technique to derive information on atmospheric aerosols - Retrieval of aerosol properties". Journal of Geophysical Research. 109 (D22): n/a. Bibcode:2004JGRD..10922205W. CiteSeerX   10.1.1.659.6946 . doi:10.1029/2004jd004904.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  14. ↑ "Tetraoxygen" . Retrieved 2025-02-21.
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