Caesium sesquioxide
Chemical compound
From Wikipedia, the free encyclopedia
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]
| Identifiers | |
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3D model (JSmol) |
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PubChem CID |
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| 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 |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Properties
The compound is often studied as an example of a Verwey type charge ordering transition at low temperatures.[5][6][7] There were some theoretical suggestions that Cs4O6 would be a ferromagnetic half metal,[8] 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.[9] 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.[10]
Preparation
It can be created by thermal decomposition of caesium superoxide at 290 °C.[11]
- 4 CsO2 → Cs4O6 + O2