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| Names | |
|---|---|
| Other names Rubidium(I) Fluoride | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.033.262 |
| RTECS number |
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| UNII | |
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| Properties | |
| RbF | |
| Molar mass | 104.4662 g/mol |
| Appearance | white crystalline solid |
| Density | 3.557 g/cm3 |
| Melting point | 795 °C (1,463 °F; 1,068 K) |
| Boiling point | 1,408 °C (2,566 °F; 1,681 K) |
| 130.6 g/100 mL (18 °C) | |
| −31.9·10−6 cm3/mol | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Toxic |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Related compounds | |
Otheranions | Rubidium chloride Rubidium bromide Rubidium iodide Rubidium astatide |
Othercations | Lithium fluoride Sodium fluoride Potassium fluoride Caesium fluoride Francium fluoride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Rubidium fluoride (RbF) is thefluoride salt ofrubidium. It is acubiccrystal withrock-salt structure.
There are several methods for synthesising rubidium fluoride. One involves reactingrubidium hydroxide withhydrofluoric acid:[1]
Another method is to neutralizerubidium carbonate with hydrofluoric acid:[1]
Another possible method is to react rubidium hydroxide withammonium fluoride:
The least used method due to expense of rubidium metal is to react it directly with fluorine gas, as rubidium reacts violently withhalogens:[1]
Rubidium fluoride is a white crystalline substance with a cubic crystal structure that looks very similar to commonsalt (NaCl). The crystals belong to thespace group Fm3m (space group no. 225) with the lattice parametera = 565 pm and four formula units perunit cell.[2] Therefractive index of the crystals is nD = 1.398.[2] Rubidium fluoride colors a flame (Bunsen burner flame) purple or magenta red (spectral analysis).
Rubidium fluoride forms two different hydrates, a sesquihydrate with the stoichiometric composition 2RbF·3H2O and a third hydrate with the composition 3RbF·H2O.[3]
In addition to simple rubidium fluoride, an acidic rubidium fluoride with the molecular formula HRbF2 is also known,[4] which can be produced by reacting rubidium fluoride and hydrogen fluoride.[4] The compounds H2RbF3 and H3RbF4 were also synthesized.[5][4]
The solubility in acetone is 0.0036 g/kg at 18 °C and 0.0039 g/kg at 37 °C.[6]
The standard enthalpy of formation of rubidium fluoride is ΔfH0298 = −552.2 kJ mol−1,[7] the standard free enthalpy of formation ΔG0298 = −520.4 kJ mol−1,[7] and the standard molar entropy S0298 = 113.9 J K −1 ·mol−1.[7] The enthalpy of solution of rubidium fluoride was determined to be −24.28 kJ/mol.[8]
| Authority control databases: National |
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