Rubidium superoxide
Names
Other names
Rubidium hyperoxide
Identifiers
3D model (JSmol)
  • InChI=1S/O2.Rb/c1-2;/q-1;+1
    Key: AFEOXRVICKHWAE-UHFFFAOYSA-N
  • O=[O-].[Rb+]
Properties
RbO2
Molar mass 117.466 g·mol−1
Appearance Bright yellow[1]
Structure
Distorted CaC2 structure[2]
Related compounds
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Rubidium superoxide or rubidium hyperoxide is a chemical compound with the chemical formula RbO2. In terms of oxidation states, the negatively charged superoxide and positively charged rubidium give it a structural formula of Rb+[O2]−.[2]

Chemistry

It can be created by slowly exposing elemental rubidium to oxygen gas:[3]

Rb(s) + O2(g) → RbO2(s)

Like other alkali metal hyperoxides, crystals can also be grown in liquid ammonia.[4]

Between 280 and 360 °C, Rubidium superoxide will decompose, leaving not rubidium sesquioxide (Rb2O3), but rather rubidium peroxide (Rb2O2).[3]

2 RbO2(s) → Rb2O2(s) + O2(g)

An even more oxygen rich compound, that of rubidium ozonide (RbO3) can be created using RbO2.[5]

Properties

Roughly speaking, RbO2 has a crystal structure similar to tetragonal calcium carbide, but is rather distorted due to the Jahn–Teller effect, which makes the crystal structure less symmetrical.[2]

RbO2 is stable in dry air, but is extremely hygroscopic.[3]

The compound has been studied as an example of magnetism arising intrinsically from the p-shell.[6] RbO2 has been predicted to be a paramagnetic Mott insulator.[7] At low temperatures, it transitions to antiferromagnetic order, with a Neel temperature of 15 K.[2]

See also

References

  1. ↑ Astuti, Fahmi; Miyajima, Mizuki; Fukuda, Takahito; Kodani, Masashi; Nakano, Takehito; Kambe, Takashi; Watanabe, Isao (2019). "Synthesis and Characterization of Magnetic Rubidium Superoxide, RbO2". Materials Science Forum. Trans Tech Publications, Ltd. 966: 237–242. doi:10.4028/www.scientific.net/msf.966.237. ISSN 1662-9752.
  2. 1 2 3 4 Labhart, M.; Raoux, D.; Känzig, W.; Bösch, M. A. (1979-07-01). "Magnetic order in 2p-electron systems: Electron paramagnetic resonance and antiferromagnetic resonance in the alkali hyperoxides KO2, RbO2, and CsO2". Physical Review B. American Physical Society (APS). 20 (1): 53–70. doi:10.1103/physrevb.20.53. ISSN 0163-1829.
  3. 1 2 3 Kraus, D. L.; Petrocelli, A. W. (1962). "The Thermal Decomposition of Rubidium Superoxide". The Journal of Physical Chemistry. American Chemical Society (ACS). 66 (7): 1225–1227. doi:10.1021/j100813a003. ISSN 0022-3654.
  4. ↑ Busch, G.; Strässler, S., eds. (1974). "Magnetische und kalorische Eigenschaften von Alkali-Hyperoxid-Kristallen". Physics of Condensed Matter. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 267–291. doi:10.1007/978-3-662-39595-0. ISBN 978-3-662-38713-9.
  5. ↑ Vol'nov, I. I.; Dobrolyubova, M. S.; Tsentsiper, A. B. (1966). "Synthesis of rubidium ozonide via rubidium superoxide". Bulletin of the Academy of Sciences, USSR Division of Chemical Science. Springer Science and Business Media LLC. 15 (9): 1611–1611. doi:10.1007/bf00848934. ISSN 0568-5230.
  6. ↑ Kováčik, Roman; Ederer, Claude (2009-10-26). "Correlation effects in p-electron magnets: Electronic structure of RbO2 from first principles". Physical Review B. American Physical Society (APS). 80 (14): 140411. arXiv:0905.3721. doi:10.1103/physrevb.80.140411. ISSN 1098-0121.
  7. ↑ Kováčik, Roman; Werner, Philipp; Dymkowski, Krzysztof; Ederer, Claude (2012-08-17). "Rubidium superoxide: A p-electron Mott insulator". Physical Review B. American Physical Society (APS). 86 (7): 075130. arXiv:1206.1423. doi:10.1103/physrevb.86.075130. ISSN 1098-0121.
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