Rubidium chloride
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Other names
rubidium(I) chloride
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Identifiers | |
3D model (
JSmol ) |
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ChEBI | |
ChemSpider | |
ECHA InfoCard
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100.029.310 |
PubChem CID
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RTECS number
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
RbCl | |
Molar mass | 120.921 g/mol |
Appearance | white crystals hygroscopic
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Density | 2.80 g/cm3 (25 °C) 2.088 g/mL (750 °C) |
Melting point | 718 °C (1,324 °F; 991 K) |
Boiling point | 1,390 °C (2,530 °F; 1,660 K) |
77 g/100mL (0 °C) 91 g/100 mL (20 °C) 130 g/100 mL (100 °C) | |
Solubility in methanol | 1.41 g/100 mL |
−46.0·10−6 cm3/mol | |
Refractive index (nD)
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1.5322 |
Thermochemistry | |
Heat capacity (C)
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52.4 J K−1 mol−1 |
Std molar
entropy (S⦵298) |
95.9 J K−1 mol−1 |
Std enthalpy of (ΔfH⦵298)formation |
−435.14 kJ/mol |
Hazards | |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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4440 mg/kg (rat) |
Safety data sheet (SDS) | Fisher Scientific |
Related compounds | |
Other anions
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Rubidium fluoride Rubidium bromide Rubidium iodide Rubidium astatide |
Other cations
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Lithium chloride Sodium chloride Potassium chloride Caesium chloride Francium chloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Rubidium chloride is the chemical compound with the formula RbCl. This alkali metal halide salt is composed of rubidium and chlorine, and finds diverse uses ranging from electrochemistry to molecular biology.
Structure
In its gas phase, RbCl is diatomic with a bond length estimated at 2.7868 Å.[1] This distance increases to 3.285 Å for cubic RbCl, reflecting the higher coordination number of the ions in the solid phase.[2]
Depending on conditions, solid RbCl exists in one of three arrangements or
Sodium chloride (octahedral 6:6)
The
Caesium chloride (cubic 8:8)
At high temperature and pressure, RbCl adopts the caesium chloride (CsCl) structure (NaCl and KCl undergo the same structural change at high pressures). Here, the chloride ions form a simple cubic arrangement with chloride anions occupying the vertices of a cube surrounding a central Rb+. This is RbCl's densest packing motif.[2] Because a cube has eight vertices, both ions' coordination numbers equal eight. This is RbCl's highest possible coordination number. Therefore, according to the radius ratio rule, cations in this polymorph will reach their largest apparent radius because the anion-cation distances are greatest.[4]
Sphalerite (tetrahedral 4:4)
The sphalerite polymorph of rubidium chloride has not been observed experimentally. This is consistent with the theory; the lattice energy is predicted to be nearly 40.0 kJ/mol smaller in magnitude than those of the preceding structures.[5]
Synthesis and reaction
The most common preparation of pure rubidium chloride involves the reaction of its hydroxide with hydrochloric acid, followed by recrystallization:[6]
- RbOH + HCl → RbCl + H2O
Because RbCl is
Rubidium chloride reacts with sulfuric acid to give rubidium hydrogen sulfate.
Radioactivity
Every 18 mg of rubidium chloride is equivalent to approximately one
Uses
- Rubidium chloride is used as a gasoline additive to improve its octane number.[7]
- Rubidium chloride has been shown to modify coupling between circadian oscillators via reduced photaic input to the suprachiasmatic nuclei. The outcome is a more equalized circadian rhythm, even for stressed organisms.[8]
- Rubidium chloride is an excellent non-invasive heart muscle.
- Rubidium chloride
- Rubidium chloride has shown apathetic depression.[11]
References
- .
- ^ a b Wells, A. F. (1984). Structural Inorganic Chemistry. Oxford University Press. pp. 410, 444.
- .
- ^ a b Shriver, D. F.; Atkins, P. W.; Cooper, H. L. (1990). "Chapter 2". Inorganic Chemistry. Freeman.
- ^ S2CID 93595759.
- ^ Winter, M. (2006). "Compounds of Rubidium". WebElements.
- ISBN 0-911910-12-3.
- PMID 8033243.
- S2CID 85691705.
- ^ "RbCl Transformation Protocol". New England Biolabs. 2006. Archived from the original on 2006-03-19.
- ISBN 978-3-642-76646-6.