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| Names | |
|---|---|
| Other names rubidium(I) chloride | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.029.310 |
| RTECS number |
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| UNII | |
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| Properties | |
| RbCl | |
| Molar mass | 120.921 g/mol |
| Appearance | white crystals hygroscopic |
| 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 inmethanol | 1.41 g/100 mL |
| −46.0·10−6 cm3/mol | |
Refractive index (nD) | 1.5322 |
| Thermochemistry | |
| 52.4 J K−1 mol−1 | |
Std molar entropy(S⦵298) | 95.9 J K−1 mol−1 |
Std enthalpy of formation(ΔfH⦵298) | −435.14 kJ/mol |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 4440 mg/kg (rat) |
| Safety data sheet (SDS) | Fisher Scientific |
| Related compounds | |
Otheranions | Rubidium fluoride Rubidium bromide Rubidium iodide Rubidium astatide |
Othercations | Lithium chloride Sodium chloride Potassium chloride Caesium chloride Francium chloride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Rubidium chloride is the chemical compound with the formulaRbCl. Thisalkali metalhalide salt is composed ofrubidium andchlorine, and finds diverse uses ranging fromelectrochemistry tomolecular biology.
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 orpolymorphs as determined with holographic imaging:[3]
Thesodium chloride (NaCl) polymorph is most common. Acubic close-packed arrangement of chlorideanions with rubidiumcations filling the octahedral holes describes this polymorph.[4] Both ions are six-coordinate in this arrangement. The lattice energy of this polymorph is only 3.2 kJ/mol less than the following structure's.[5]
At high temperature and pressure, RbCl adopts thecaesium chloride (CsCl) structure (NaCl and KCl undergo the same structural change at high pressures). Here, the chloride ions form asimple 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]
The sphalerite polymorph of rubidium chloride has not been observed experimentally. This is consistent with the theory; thelattice energy is predicted to be nearly 40.0 kJ/mol smaller in magnitude than those of the preceding structures.[5]
The most common preparation of pure rubidium chloride involves the reaction of itshydroxide withhydrochloric acid, followed byrecrystallization:[6]
Because RbCl ishygroscopic, it must be protected from atmospheric moisture, e.g. using adesiccator. RbCl is primarily used in laboratories. Therefore, numerous suppliers (see below) produce it in smaller quantities as needed. It is offered in a variety of forms for chemical and biomedical research.
Rubidium chloride reacts with sulfuric acid to giverubidium hydrogen sulfate.
Every 18 mg of rubidium chloride is equivalent to approximately onebanana equivalent dose due to the large fraction (27.8%) of naturally occurring radioactive isotoperubidium-87.
