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| Names | |||
|---|---|---|---|
| IUPAC name Cadmium dichloride | |||
| Other names Cadmium(II) chloride | |||
| Identifiers | |||
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3D model (JSmol) |
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| 3902835 | |||
| ChEBI | |||
| ChemSpider | |||
| ECHA InfoCard | 100.030.256 | ||
| EC Number |
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| 912918 | |||
| KEGG | |||
| RTECS number |
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| UNII |
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| UN number | 2570 | ||
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| Properties | |||
| CdCl2 | |||
| Molar mass | 183.31 g·mol−1 | ||
| Appearance | White solid,hygroscopic | ||
| Odor | Odorless | ||
| Density | 4.047 g/cm3 (anhydrous)[1] 3.26 g/cm3 (monohydrate) 3.327 g/cm3 (Hemipentahydrate)[2] | ||
| Melting point | 568 °C (1,054 °F; 841 K)[2] | ||
| Boiling point | 964 °C (1,767 °F; 1,237 K)[2] | ||
| Hemipentahydrate: 79.5 g/100 mL (−10 °C) 90 g/100 mL (0 °C) Monohydrate: 119.6 g/100 mL (25 °C)[2] 134.3 g/100 mL (40 °C) 134.2 g/100 mL (60 °C) 147 g/100 mL (100 °C)[3] | |||
| Solubility | Soluble inalcohol,selenium(IV) oxychloride,benzonitrile Insoluble inether,acetone[1] | ||
| Solubility inpyridine | 4.6 g/kg (0 °C) 7.9 g/kg (4 °C) 8.1 g/kg (15 °C) 6.7 g/kg (30 °C) 5 g/kg (100 °C)[1] | ||
| Solubility inethanol | 1.3 g/100 g (10 °C) 1.48 g/100 g (20 °C) 1.91 g/100 g (40 °C) 2.53 g/100 g (70 °C)[1] | ||
| Solubility indimethyl sulfoxide | 18 g/100 g (25 °C)[1] | ||
| Vapor pressure | 0.01 kPa (471 °C) 0.1 kPa (541 °C)[2] | ||
| −6.87·10−5 cm3/mol[2] | |||
| Viscosity | 2.31 cP (597 °C) 1.87 cP (687 °C)[1] | ||
| Structure | |||
| Rhombohedral,hR9 (anhydrous)[4] Monoclinic (hemipentahydrate)[3] | |||
| R3m, No. 166 (anhydrous)[4] | |||
| 3 2/m (anhydrous)[4] | |||
a = 3.846 Å,c = 17.479 Å (anhydrous)[4] α = 90°, β = 90°, γ = 120° | |||
| Thermochemistry | |||
| 74.7 J/mol·K[2] | |||
Std molar entropy(S⦵298) | 115.3 J/mol·K[2] | ||
Std enthalpy of formation(ΔfH⦵298) | −391.5 kJ/mol[2] | ||
Gibbs free energy(ΔfG⦵) | −343.9 kJ/mol[2] | ||
| Hazards | |||
| GHS labelling: | |||
   [5] | |||
| Danger | |||
| H301,H330,H340,H350,H360,H372,H410[5] | |||
| P210,P260,P273,P284,P301+P310,P310[5] | |||
| NFPA 704 (fire diamond) | |||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) | 94 mg/kg (rats, oral)[1] 60 mg/kg (mouse, oral) 88 mg/kg (rat, oral)[7] | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) | [1910.1027] TWA 0.005 mg/m3 (as Cd)[6] | ||
REL (Recommended) | Ca[6] | ||
IDLH (Immediate danger) | Ca [9 mg/m3 (as Cd)][6] | ||
| Safety data sheet (SDS) | External MSDS | ||
| Related compounds | |||
Otheranions | Cadmium fluoride Cadmium bromide Cadmium iodide | ||
Othercations | Zinc chloride Mercury(II) chloride Calcium chloride | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Cadmium chloride is a white crystalline compound ofcadmium andchloride, with the formula CdCl2. This salt is ahygroscopic solid that is highly soluble in water and slightly soluble inalcohol. Thecrystal structure of cadmium chloride (described below), is a reference for describing other crystal structures. Also known are CdCl2•H2O and the hemipentahydrate CdCl2•2.5H2O.[2]
Anhydrous cadmium chloride forms a layered structure consisting of octahedral Cd2+ centers linked with chloride ligands.Cadmium iodide, CdI2, has a similar structure, but theiodide ions are arranged in aHCP lattice, whereas in CdCl2 thechloride ions are arranged in a CCP lattice.[8][9]
The anhydrous form absorbs moisture from the air to form varioushydrates. Three of these hydrates have been examined byX-ray crystallography.
| Compound | CdCl2·H2O[10] | CdCl2·2.5H2O[11] | CdCl2·4H2O[12] |
|---|---|---|---|
| Molar mass (g/mol) | 201.33 | 228.36 | 255.38 |
| Crystal Structure | Orthorhombic | Monoclinic | Orthorhombic |
| Space Group | Pnma | P21/n | P212121 |
| Lattice constant a (Å) | 9.25 | 9.21 | 12.89 |
| Lattice constant b (Å) | 3.78 | 11.88 | 7.28 |
| Lattice constant c (Å) | 11.89 | 10.08 | 15.01 |
| β | 93.5° | ||
| Density (g/cm3) | 3.26 | 2.84 | 2.41 |
| Comment | Interconnected CdCl3(H2O) octahederons | Distortedtrans-[CdCl2(H2O)4] octahedrons |
Cadmium chloride dissolves well in water and other polar solvents. It is a mildLewis acid.[8]
Solutions of equimolar cadmium chloride and potassium chloride give potassium cadmium trichloride.[13]With large cations, it is possible to isolate thetrigonal bipyramidal [CdCl5]3− ion.
Cadmium metal is soluble in molten cadmium chloride, produced by heating cadmium chloride above 568 °C. Upon cooling, the metal precipitates.[14]
Anhydrous cadmium chloride can be prepared by the reaction ofhydrochloric acid and cadmium metal orcadmium oxide.[14]
The anhydrous salt can also be prepared from anhydrous cadmium acetate using hydrogen chloride or acetyl chloride.[15]
Industrially, it is produced by the reaction of molten cadmium andchlorine gas at 600 °C.[14]
The monohydrate, hemipentahydrate, and tetrahydrate can be produced by evaporation of the solution of cadmium chloride at 35, 20, and 0 °C respectively. The hemipentahydrate and tetrahydrate release water in air.[10][11][12]
Cadmium chloride is used for the preparation ofcadmium sulfide, used as "cadmium yellow", a brilliant-yellow stable inorganicpigment.[14]
In the laboratory, anhydrous CdCl2 can be used for the preparation oforganocadmium compounds of the type R2Cd, where R is anaryl or a primaryalkyl. These were once used in the synthesis ofketones fromacyl chlorides:[16]
Such reagents have largely been supplanted byorganocopper compounds, which are much less toxic.
Cadmium chloride is also used forphotocopying, dyeing andelectroplating.
It was used in the first experiments for detecting neutrinos, theCowan–Reines neutrino experiment.
Like all cadmium compounds,CdCl
2 is highly toxic and appropriate safety precautions must be taken when handling it.
