Wikipedia

Caesium sesquioxide

Caesium sesquioxide is a chemical compound with the formula Cs2O3 or more accurately Cs4O6. It is an oxide of caesium containing oxygen in different oxidation states. It consists of caesium cations Cs+, superoxide anions O−2 and peroxide anions O2−2. Caesium in this compound has an oxidation state of +1, while oxygen in superoxide has an oxidation state of −1/2 and oxygen in peroxide has an oxidation state of −1. This compound has a structural formula of (Cs+)4(O−2)2(O2−2).[1][2] Compared to the other caesium oxides, this phase is less well studied,[3] but has been long present in the literature.[4] It can be created by thermal decomposition of caesium superoxide at 290 °C.[5]

Caesium sesquioxide
Identifiers
3D model (JSmol)
  • InChI=1S/4Cs.2HO2.O2/c;;;;3*1-2/h;;;;2*1H;/q4*+1;;;-2/p-2
    Key: CBAPCGFDLAJQPQ-UHFFFAOYSA-L
  • [Cs+].[Cs+].[Cs+].[Cs+].[O-][O].[O-][O].[O-][O-]
Properties
Cs4O6
Molar mass 627.616 g·mol−1
Appearance black powder[1]
Structure[1]
Pu2C3 structure type (body-centered cubic)
I43d (no. 220)
a = 984.6 pm
Related compounds
Other cations
 Rubidium sesquioxide
Related caesium oxides
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
4 CsO2 → Cs4O6 + O2

The compound is often studied as an example of a Verwey type charge ordering transition at low temperatures.[6][7][8] There were some theoretical suggestions that Cs4O6 would be a ferromagnetic half metal,[9] but along with the closely related rubidium sesquioxide, experimental results found a magnetically frustrated system.[1] Below about 200 K, the structure changes to tetragonal symmetry.[10] Electron paramagnetic resonance and nuclear magnetic resonance measurements show a complicated low temperature magnetic behavior that depends on the orientation of the oxygen dimers and superexchange through the caesium atoms.[11]

References

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  1. ^ a b c d Winterlik, Jürgen; Fecher, Gerhard H.; Jenkins, Catherine A.; Medvedev, Sergey; Felser, Claudia; et al. (2009-06-09). "Exotic magnetism in the alkali sesquioxides Rb4O6 and Cs4O6". Physical Review B. 79 (21): 214410. arXiv:0904.4338. Bibcode:2009PhRvB..79u4410W. doi:10.1103/physrevb.79.214410. ISSN 1098-0121. S2CID 118706339.
  2. ^ "Chempendix - Oxidation States".
  3. ^ Band, A.; Albu-Yaron, A.; Livneh, T.; Cohen, H.; Feldman, Y.; Shimon, L.; Popovitz-Biro, R.; Lyahovitskaya, V.; Tenne, R. (2004-07-27). "Characterization of Oxides of Cesium". The Journal of Physical Chemistry B. 108 (33). American Chemical Society (ACS): 12360–12367. doi:10.1021/jp036432o. ISSN 1520-6106.
  4. ^ Helms, Alfred; Klemm, Wilhelm (1939-08-29). "Über die Kristallstrukturen der Rubidium- und Cäsiumsesquioxyde". Zeitschrift für anorganische und allgemeine Chemie (in German). 242 (2). Wiley: 201–214. doi:10.1002/zaac.19392420210. ISSN 0863-1786.
  5. ^ Merz, Patrick; Schmidt, Marcus; Felser, Claudia; Jansen, Martin (2017-03-24). "Thermo-analytical Investigations on the Superoxides AO2 (A = K, Rb, Cs), Revealing Facile Access to Sesquioxides A4O6". Zeitschrift für anorganische und allgemeine Chemie. 643 (8). Wiley: 544–547. doi:10.1002/zaac.201700013. ISSN 0044-2313.
  6. ^ Max Planck Society (2018-01-19). "Charge order and electron localization in a molecule-based solid". Phys.org. Retrieved 2021-11-26.
  7. ^ Adler, Peter; Jeglič, Peter; Reehuis, Manfred; Geiß, Matthias; Merz, Patrick; Knaflič, Tilen; Komelj, Matej; Hoser, Andreas; Sans, Annette; Janek, Jürgen; Arčon, Denis; Jansen, Martin; Felser, Claudia (2018-01-17). "Verwey-type charge ordering transition in an open-shell p -electron compound". Science Advances. 4 (1). American Association for the Advancement of Science (AAAS): eaap7581. Bibcode:2018SciA....4.7581A. doi:10.1126/sciadv.aap7581. ISSN 2375-2548. PMC 5775027. PMID 29372183.
  8. ^ Colman, Ross H.; Okur, H. Esma; Kockelmann, Winfried; Brown, Craig M.; Sans, Annette; Felser, Claudia; Jansen, Martin; Prassides, Kosmas (2019-10-21). "Elusive Valence Transition in Mixed-Valence Sesquioxide Cs4O6". Inorganic Chemistry. 58 (21). American Chemical Society (ACS): 14532–14541. doi:10.1021/acs.inorgchem.9b02122. ISSN 0020-1669. PMC 7880551. PMID 31633914.
  9. ^ Attema, J J; Wijs, G A de; Groot, R A de (2007-04-05). "Spintronic materials based on main-group elements" (PDF). Journal of Physics: Condensed Matter. 19 (16). IOP Publishing: 165203. Bibcode:2007JPCM...19p5203A. doi:10.1088/0953-8984/19/16/165203. ISSN 0953-8984. S2CID 98543752.
  10. ^ Okur, H. Esma; Colman, Ross H.; Ohishi, Yasuo; Sans, Annette; Felser, Claudia; Jansen, Martin; Prassides, Kosmas (2020-01-06). "Pressure-Induced Charge Disorder–Order Transition in the Cs4O6 Sesquioxide". Inorganic Chemistry. 59 (2). American Chemical Society (ACS): 1256–1264. doi:10.1021/acs.inorgchem.9b02974. ISSN 0020-1669. PMID 31904961. S2CID 210041198.
  11. ^ Arčon, D.; Anderle, K.; Klanjšek, M.; Sans, A.; Mühle, C.; Adler, P.; Schnelle, W.; Jansen, M.; Felser, C. (2013-12-10). "Influence of O2 molecular orientation on p-orbital ordering and exchange pathways in Cs4O6". Physical Review B. 88 (22). American Physical Society (APS): 224409. Bibcode:2013PhRvB..88v4409A. doi:10.1103/physrevb.88.224409. ISSN 1098-0121.
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