Rubidium superoxide
Chemical compound
From Wikipedia, the free encyclopedia
Rubidium superoxide, rubidio superoxide or rubidium hyperoxide is a chemical compound with the chemical formula RbO2. Rubidium forms superoxide under certain conditions like direct contact with oxygen. In terms of oxidation states, the negatively charged superoxide and positively charged rubidium give it a structural formula of Rb+[O2]−.[2]
| Names | |
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| Other names
Rubidium hyperoxide, rubidio superoxide | |
| Identifiers | |
3D model (JSmol) |
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CompTox Dashboard (EPA) |
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| Properties | |
| RbO2 | |
| Molar mass | 117.466 g·mol−1 |
| Appearance | Bright yellow[1] |
| Structure | |
| Distorted CaC2 structure[2] | |
| Related compounds | |
Other cations |
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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
RbO2 is stable in dry air, but is extremely hygroscopic.[3] 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)
The compound has been studied as an example of magnetism arising intrinsically from the p-shell.[4] RbO2 has been predicted to be a paramagnetic Mott insulator.[5] At low temperatures, it transitions to antiferromagnetic order, with a Neel temperature of 15 K.[2]
Structure
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]
Preparation
Reactions
An even more oxygen rich compound, that of rubidium ozonide (RbO3) can be created by reacting RbO2 with ozone.[7]