Chromium(II) chloride
Chromium(II) chloride describes inorganic compounds with the formula CrCl2(H2O)n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily dissolves in water to give bright blue air-sensitive solutions of the tetrahydrate Cr(H2O)4Cl2. Chromium(II) chloride has no commercial uses but is used on a laboratory-scale for the synthesis of other chromium complexes.
| Names | |
|---|---|
| IUPAC name
Chromium(II) chloride | |
| Other names
Chromous chloride | |
| Identifiers | |
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3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.030.136 |
| EC Number |
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PubChem CID |
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| RTECS number |
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| UNII |
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| UN number | 3077 |
CompTox Dashboard (EPA) |
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SMILES
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| Properties | |
| Cl2Cr | |
| Molar mass | 122.90 g·mol−1 |
| Appearance | White to grey/green powder (anhydrous) blue solid (tetrahydrate) |
| Odor | Odorless |
| Density | 2.88 g/cm3 (24 °C) |
| Melting point | 824 °C (1,515 °F; 1,097 K) anhydrous 51 °C (124 °F; 324 K) tetrahydrate, decomposes |
| Boiling point | 1,302 °C (2,376 °F; 1,575 K) anhydrous |
| Soluble | |
| Solubility | Insoluble in alcohol, ether |
| Acidity (pKa) | 2 |
Magnetic susceptibility (χ) |
+7230·10−6 cm3/mol |
| Structure | |
| Orthorhombic (deformed rutile, anhydrous), oP6 Monoclinic (tetrahydrate) | |
Space group |
Pnnm, No. 58 (anhydrous) P21/c, No. 14 (tetrahydrate) |
Point group |
2/m 2/m 2/m (anhydrous) 2/m (tetrahydrate) |
a = 6.64 Å, b = 5.98 Å, c = 3.48 Å (anhydrous) α = 90°, β = 90°, γ = 90° | |
| Octahedral (Cr2+, anhydrous) | |
| Thermochemistry | |
Heat capacity (C) |
71.2 J/mol·K |
Std molar entropy (S⦵298) |
115.3 J/mol·K |
Std enthalpy of formation (ΔfH⦵298) |
−395.4 kJ/mol |
Gibbs free energy (ΔfG⦵) |
−356 kJ/mol |
| Hazards | |
| GHS labelling: | |
| Warning | |
| H302, H315, H319, H335 | |
| P261, P305+P351+P338 | |
| NFPA 704 (fire diamond) |
2
0
1 |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
1870 mg/kg (rats, oral) |
| Safety data sheet (SDS) | Oxford MSDS |
| Related compounds | |
Other anions |
Chromium(II) fluoride Chromium(II) bromide Chromium(II) iodide |
Other cations |
Chromium(III) chloride Chromium(IV) chloride Molybdenum(II) chloride Tungsten(II) chloride |
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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