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]
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Other names
Rubidium hyperoxide
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Identifiers | |
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3D model (JSmol)
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Properties | |
RbO2 | |
Molar mass | 117.466 g·mol−1 |
Appearance | Bright yellow[1] |
Structure | |
Distorted CaC2 structure[2] | |
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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).
Infobox references
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It can be created by slowly exposing elemental rubidium to oxygen gas:[3]
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]
An even more oxygen rich compound, that of rubidium ozonide (RbO3) can be created using RbO2.[5]
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]