Cadmium chloride

Cadmium chloride
Names
IUPAC name
Cadmium dichloride
Other names
Cadmium(II) chloride
Identifiers
10108-64-2 Yes
34330-64-8 (monohydrate)
ChEBI CHEBI:35456 Yes
ChemSpider 23035 Yes
EC number 233-296-7
Jmol-3D images Image
PubChem 24947
RTECS number EV0175000
UNII J6K4F9V3BA Yes
UN number 2570
Properties
Molecular formula
 CdCl2
Molar mass 183.32 g·mol−1
Appearance White solid, hygroscopic
Odor Odorless
Density 4.047 g/cm3 (anhydrous)[1]
3.327 g/cm3 (pentahydrate)[2]
Melting point 568 °C (1,054 °F; 841 K)
at 760 mmHg[2]
Boiling point 964 °C (1,767 °F; 1,237 K)
at 760 mmHg[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 in alcohol, selenium(IV) oxychloride, benzonitrile
Insoluble in ether, acetone[1]
Solubility in pyridine 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 in ethanol 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 in dimethyl 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
Crystal structure Rhombohedral, hR9 (anhydrous)[4]
Monoclinic (hemipentahydrate)[3]
Space group R3m, No. 166 (anhydrous)[4]
Point group 3 2/m (anhydrous)[4]
Lattice constant a = 3.846 Å, c = 17.479 Å (anhydrous)[4]
Lattice constant α = 90°, β = 90°, γ = 120°
Thermochemistry
Specific
heat capacity (C)
 74.7 J/mol·K[2]
115.3 J/mol·K[2]
Std enthalpy of
formation (ΔfHo298)
 −391.5 kJ/mol[2]
−343.9 kJ/mol[2]
Hazards
MSDS External MSDS
GHS pictograms [5]
GHS signal word Danger
H301, H330, H340, H350, H360, H372, H410[5]
P210, P260, P273, P284, P301+310, P310[5]
EU Index 048-008-00-3
EU classification T+ N
Carc. Cat. 2
Muta. Cat. 2
Repr. Cat. 2
R-phrases R45, R46, R60, R61, R25, R26, R48/23/25, R50/53
S-phrases S53, S45, S60, S61
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
1
3
0
94 mg/kg (rats, oral)[1]
Related compounds
Other anions
 Cadmium fluoride
Cadmium bromide
Cadmium iodide
Other cations
 Zinc chloride
Mercury(II) chloride
Calcium chloride
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Cadmium chloride is a white crystalline compound of cadmium and chlorine, with the formula CdCl2. It is a hygroscopic solid that is highly soluble in water and slightly soluble in alcohol. Although it is considered to be ionic, it has considerable covalent character to its bonding. The crystal structure of cadmium chloride (described below), composed of two-dimensional layers of ions, is a reference for describing other crystal structures. Also known are CdCl2.H2O and CdCl2.5H2O.[2]

Structure

Cadmium chloride forms crystals with rhombohedral symmetry. Cadmium iodide, CdI2, has a very similar crystal structure to CdCl2. The individual layers in the two structures are identical, but in CdCl2 the chloride ions are arranged in a CCP lattice, whereas in CdI2 the iodide ions are arranged in an HCP lattice.[6][7]

Chemical properties

Cadmium chloride dissolves well in water and other polar solvents. In water, its high solubility is due in part to formation of complex ions such as [CdCl4]2−. Because of this behavior, CdCl2 is a mild Lewis acid).[6]

CdCl2 + 2 Cl− → [CdCl4]2−

With large cations, it is possible to isolate the trigonal bipyramidal [CdCl5]3− ion.

Preparation

Anhydrous cadmium chloride can be prepared by the action of anhydrous chlorine or hydrogen chloride gas on heated cadmium metal.

Cd + 2 HCl → CdCl2 + H2

Hydrochloric acid may be used to make hydrated CdCl2 from the metal, or from cadmium oxide or cadmium carbonate.

Uses

Cadmium chloride is used for the preparation of cadmium sulfide, used as "Cadmium Yellow", a brilliant-yellow stable inorganic pigment.

CdCl
2 + H
2S → CdS + 2 HCl

In the laboratory, anhydrous CdCl2 can be used for the preparation of organocadmium compounds of the type R2Cd, where R is an aryl or a primary alkyl. These were once used in the synthesis of ketones from acyl chlorides:[8]

CdCl
2 + 2 RMgX → R
2Cd + MgCl
2 + MgX
2
R
2Cd + R'COCl → R'COR + CdCl
2

Such reagents have largely been supplanted by organocopper compounds, which are much less toxic.

Cadmium chloride is also used for photocopying, dyeing and electroplating.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Anatolievich, Kiper Ruslan. "cadmium chloride". http://chemister.ru''. Retrieved 2014-06-25.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  3. ↑ 3.0 3.1 Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). New York: D. Van Nostrand Company. p. 169.
  4. ↑ 4.0 4.1 4.2 4.3 "Cadmium Chloride - CdCl2". http://wwwchem.uwimona.edu.jm''. Mona, Jamaica: The University of the West Indies. Retrieved 2014-06-25.
  5. ↑ 5.0 5.1 5.2 Sigma-Aldrich Co., Cadmium chloride. Retrieved on 2014-05-23.
  6. ↑ 6.0 6.1 N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
  7. ↑ A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
  8. ↑ J. March, Advanced Organic Chemistry, 4th ed., p. 723, Wiley, New York, 1992.

External links

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