Rubidium oxide
Rubidium oxide is the chemical compound with the formula Rb2O. Rubidium oxide is highly reactive towards water, and therefore it would not be expected to occur naturally. The rubidium content in minerals is often calculated and quoted in terms of Rb2O. In reality, the rubidium is typically present as a component of (actually, an impurity in) silicate or aluminosilicate. A major source of rubidium is lepidolite, KLi2Al(Al,Si)3O10(F,OH)2, wherein Rb sometimes replaces K.
| Names | |
|---|---|
| IUPAC name
Rubidium oxide | |
| Other names
Rubidium(I) oxide Dirubidium oxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.038.161 |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| Rb2O | |
| Molar mass | 186.94 g/moL |
| Appearance | Yellow solid |
| Density | 4 g/cm3 |
| Melting point | >500 °C |
| Reacts to give RbOH | |
| +1527.0·10−6 cm3/mol | |
| Structure | |
| Antifluorite (cubic), cF12 | |
| Fm3m, No. 225 | |
| Tetrahedral (Rb+); cubic (O2−) | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Corrosive, reacts violently with water |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Related compounds | |
Other anions |
Rubidium sulfide Rubidium selenide Rubidium telluride Rubidium polonide |
Other cations |
Lithium oxide Sodium oxide Potassium oxide Caesium oxide |
| Rubidium suboxide Rubidium peroxide Rubidium sesquioxide Rubidium superoxide Rubidium ozonide | |
Related compounds |
Rubidium hydroxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
Rb2O is a yellow colored solid. The related species Na2O, K2O, and Cs2O are colorless, pale-yellow, and orange, respectively.
The alkali metal oxides M2O (M = Li, Na, K, Rb) crystallise in the antifluorite structure. In the antifluorite motif the positions of the anions and cations are reversed relative to their positions in CaF2, with rubidium ions 4-coordinate (tetrahedral) and oxide ions 8-coordinate (cubic).