Solid oxygen

Source: Wikipedia, the free encyclopedia.
This article is about the solid phase of elemental oxygen. For solids used as a source of oxygen or as an oxidizer, see Oxidizing agent.

Solid oxygen is the solid ice phase of oxygen. It forms below 54.36 K (−218.79 °C; −361.82 °F) at standard atmospheric pressure. Solid oxygen O2, like liquid oxygen, is a clear substance with a light sky-blue color caused by absorption in the red part of the visible light spectrum.

Oxygen molecules have a relationship between the

superconducting state.[4] Structural investigations of solid oxygen began in the 1920s and, at present, six distinct crystallographic phases
are established unambiguously.

The density of solid oxygen ranges from 21 cm3/mol in the α-phase, to 23.5 cm3/mol in the γ-phase.[5]

Phases

Phase diagram for solid oxygen

Six different phases of solid oxygen are known to exist:[1][6]

  1. α-phase: light blue – forms at 1 atm, below 23.8 K,
    monoclinic crystal structure, space group
    C2/m (no. 12).
  2. β-phase: faint blue to pink – forms at 1 atm, below 43.8 K, rhombohedral crystal structure, space group R3m (no. 166). At room temperature and high pressure begins transformation to tetraoxygen.
  3. γ-phase: faint blue – forms at 1 atm, below 54.36 K, cubic crystal structure, Pm3n (no. 223).[7][8]
  4. δ-phase: orange – forms at room temperature at a pressure of 9 GPa
  5. ε-phase: dark-red to black – forms at room temperature at pressures greater than 10 GPa
  6. ζ-phase: metallic – forms at pressures greater than 96 GPa

It has been found that oxygen is solidified into a state called the β-phase at room temperature by applying pressure, and with further increasing pressure, the β-phase undergoes

molecular interactions, the color of the β-phase changes to pink, orange, then red (the stable octaoxygen phase), and the red color further darkens to black with increasing pressure. It was found that a metallic ζ-phase appears at 96 GPa when ε-phase oxygen is further compressed.[6]

Red oxygen

Main article: Octaoxygen

As the pressure of oxygen at room temperature is increased through 10 gigapascals (1,500,000 psi), it undergoes a dramatic phase transition. Its volume decreases significantly[9] and it changes color from sky-blue to deep red.[10] However, this is a different allotrope of oxygen, O
8, not merely a different crystalline phase of O2.

Ball-and-stick model of O8 Part of the crystal structure of ε-oxygen

Metallic oxygen

A

ζ-phase appears at 96 GPa when ε-phase oxygen is further compressed.[9] This phase was discovered in 1990 by pressurizing oxygen to 132 GPa.[3] The ζ-phase with metallic cluster[11] exhibits superconductivity at pressures over 100 GPa and a temperature below 0.6 K.[4][6]

References

  1. ^
    doi:10.1016/j.physrep.2004.06.002
    .
  2. ^ See also: For papers dealing with the magnetic properties of solid oxygen we refer to magnetisation of condensed oxygen under high pressures and in strong magnetic fields by R.J. Meier, C.J. Schinkel and A. de Visser, J. Phys. C15 (1982) 1015–1024, far infrared absorption dealing with the magnetic excitations or spinwaves in Meier R J, Colpa J H P and Sigg H 1984 J. Phys. C: Solid State Phys. 17 4501.
  3. ^
    doi:10.1021/j100366a020.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  4. ^
    S2CID 205001394.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  5. doi:10.1063/1.555582
    .
  6. ^ a b c Advanced Industrial Science and Technology (AIST) (2006). "Solid Oxygen ε-Phase Crystal Structure Determined Along With The Discovery of a Red Oxygen O8 Cluster". AZoNano. Retrieved 2008-01-10.
  7. ISSN 0365-110X
    .
  8. ISSN 0163-1829
    .
  9. ^
    PMID 10058574
    .
  10. doi:10.1016/0009-2614(79)80066-4
    .
  11. PMID 12465476
    .
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