Cadmium chloride

Summary

Cadmium chloride is a white crystalline compound of cadmium and chloride, with the formula CdCl2. This salt is a hygroscopic solid that is highly soluble in water and slightly soluble in alcohol. The crystal structure of cadmium chloride (described below), is a reference for describing other crystal structures. Also known are CdCl2•H2O and CdCl2•5H2O.[2]

Cadmium chloride
Ball-and-stick model of cadmium chloride
Cadmium chloride in polyhedron shape
Cadmium chloride hemipentahydrate
Names
IUPAC name
Cadmium dichloride
Other names
Cadmium(II) chloride
Identifiers
  • 10108-64-2 checkY
  • 7790-78-5 (hemipentahydrate) checkY
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:35456 checkY
ChemSpider
  • 23035 checkY
ECHA InfoCard 100.030.256 Edit this at Wikidata
EC Number
  • 233-296-7
912918
KEGG
  • C15233
  • 24947
RTECS number
  • EV0175000
UNII
  • J6K4F9V3BA checkY
  • 2R707SXC9H (hemipentahydrate) checkY
UN number 2570
  • DTXSID6020226 Edit this at Wikidata
  • InChI=1S/Cd.2ClH/h;2*1H/q+2;;/p-2 checkY
    Key: YKYOUMDCQGMQQO-UHFFFAOYSA-L checkY
  • InChI=1/Cd.2ClH/h;2*1H/q+2;;/p-2
    Key: YKYOUMDCQGMQQO-NUQVWONBAG
  • [Cd+2].[Cl-].[Cl-]
Properties
CdCl2
Molar mass 183.31 g·mol−1
Appearance White solid, hygroscopic
Odor Odorless
Density 4.047 g/cm3 (anhydrous)[1]
3.327 g/cm3 (Hemipentahydrate)[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
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]
115.3 J/mol·K[2]
−391.5 kJ/mol[2]
−343.9 kJ/mol[2]
Hazards
GHS labelling:
GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard[5]
Danger
H301, H330, H340, H350, H360, H372, H410[5]
P210, P260, P273, P284, P301+P310, P310[5]
NFPA 704 (fire diamond)
4
0
0
Lethal dose or concentration (LD, LC):
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
Other anions
Cadmium fluoride
Cadmium bromide
Cadmium iodide
Other cations
Zinc chloride
Mercury(II) chloride
Calcium 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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Infobox references

StructureEdit

Cadmium chloride forms a layered structure consisting of octahedral Cd2+ centers linked with chloride ligands. Cadmium iodide, CdI2, has a similar structure but the chloride ions are arranged in a CCP lattice, whereas in CdI2 the iodide ions are arranged in an HCP lattice.[8][9]

Chemical propertiesEdit

Cadmium chloride dissolves well in water and other polar solvents. It is a mild Lewis acid.[8]

CdCl2 + 2 Cl → [CdCl4]2−

Solutions of equimolar cadmium chloride and potassium chloride give potassium cadmium trichloride.[10] With large cations, it is possible to isolate the trigonal bipyramidal [CdCl5]3− ion.

PreparationEdit

Anhydrous cadmium chloride can be prepared by the reaction of hydrochloric acid and cadmium metal.

Cd + 2 HCl → CdCl2 + H2

The anhydrous salt can also be prepared from anhydrous cadmium acetate using hydrogen chloride or acetyl chloride.[11]

UsesEdit

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

CdCl
2
+ H
2
S
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:[12]

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

ReferencesEdit

  1. ^ a b c d e f g Anatolievich, Kiper Ruslan. "cadmium chloride". chemister.ru. Retrieved 2014-06-25.
  2. ^ a b c d e f g h i j k 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. ^ a b Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). New York: D. Van Nostrand Company. p. 169.
  4. ^ a b c d "Cadmium Chloride - CdCl2". chem.uwimona.edu.jm. Mona, Jamaica: The University of the West Indies. Retrieved 2014-06-25.
  5. ^ a b c Sigma-Aldrich Co., Cadmium chloride. Retrieved on 2014-05-23.
  6. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0087". National Institute for Occupational Safety and Health (NIOSH).
  7. ^ "Cadmium compounds (as Cd)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  8. ^ a b N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
  9. ^ A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
  10. ^ F. Wagenknecht; R. Juza (1963). "Potassium cadmium chloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1095.
  11. ^ F. Wagenknecht; R. Juza (1963). "Cadmium chloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. pp. 1093–4.
  12. ^ J. March, Advanced Organic Chemistry, 4th ed., p. 723, Wiley, New York, 1992.

External linksEdit

  • International Chemical Safety Card 0116
  • IARC Monograph "Cadmium and Cadmium Compounds"
  • National Pollutant Inventory - Cadmium and compounds