Cadmium chloride

Names

IUPAC name

Cadmium dichloride

Other names

Cadmium(II) chloride

Identifiers

CAS Number

10108-64-2^Y
(hemipentahydrate): 7790-78-5^Y
(monohydrate): 35658-65-2

3D model (JSmol)

Interactive image
(hemipentahydrate): Interactive image
(monohydrate): Interactive image

Beilstein Reference

3902835

ChEBI

CHEBI:35456^Y

ChemSpider

23035^Y
(hemipentahydrate): 17339510
(monohydrate): 4447434

ECHA InfoCard

100.030.256

EC Number

233-296-7
(hemipentahydrate): 813-696-3

Gmelin Reference

912918

KEGG

C15233

PubChem CID

24947
(hemipentahydrate): 24978551
(monohydrate): 5284356

RTECS number

EV0175000

UNII

J6K4F9V3BA^Y
(hemipentahydrate): 2R707SXC9H^Y

UN number

2570

CompTox Dashboard (EPA)

DTXSID6020226
(hemipentahydrate): DTXSID4040183

InChI

InChI=1S/Cd.2ClH/h;2*1H/q+2;;/p-2^Y
Key: YKYOUMDCQGMQQO-UHFFFAOYSA-L^Y
InChI=1/Cd.2ClH/h;2*1H/q+2;;/p-2
Key: YKYOUMDCQGMQQO-NUQVWONBAG
(hemipentahydrate): InChI=1S/2Cd.4ClH.5H2O/h;;4*1H;5*1H2/q2*+2;;;;;;;;;/p-4
Key: DZVRGWYMCGLNKJ-UHFFFAOYSA-J
(monohydrate): InChI=1S/Cd.2ClH.H2O/h;2*1H;1H2/q+2;;;/p-2
Key: OISMQLUZKQIKII-UHFFFAOYSA-L

SMILES

[Cd+2].[Cl-].[Cl-]
(hemipentahydrate): O.O.O.O.O.[Cl-].[Cl-].[Cl-].[Cl-].[Cd+2].[Cd+2]
(monohydrate): O.[Cl-].[Cl-].[Cd+2]

Properties

Chemical formula

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]

Solubility in water

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]

Magnetic susceptibility (χ)

−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]

α = 90°, β = 90°, γ = 120°

Thermochemistry

Heat capacity (C)

74.7 J/mol·K^[2]

Std molar
entropy (S^⦵₂₉₈)

115.3 J/mol·K^[2]

Std enthalpy of
formation (Δ_fH^⦵₂₉₈)

−391.5 kJ/mol^[2]

Gibbs free energy (Δ_fG^⦵)

−343.9 kJ/mol^[2]

Hazards

GHS labelling:

Pictograms

^[5]

Signal word

Danger

Hazard statements

H301, H330, H340, H350, H360, H372, H410^[5]

Precautionary statements

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

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).

N verify (what is ^YN ?)

Infobox references

Chemical compound

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 the hemipentahydrate CdCl₂•2.5H₂O.^[2]

Structure

Anhydrous

Anhydrous cadmium chloride forms a layered structure consisting of octahedral Cd²⁺ centers linked with chloride ligands. Cadmium iodide, CdI₂, has a similar structure, but the iodide ions are arranged in a HCP lattice, whereas in CdCl₂ the chloride ions are arranged in a CCP lattice.^[8]^[9]

Hydrates

The anhydrous form absorbs moisture from the air to form various hydrates. Three of these hydrates have been examined by X-ray crystallography.

Crystallographic data for the 3 hydrates of cadmium chloride
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		Distorted trans-[CdCl₂(H₂O)₄] octahedrons

Chemical properties

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.^[13] With large cations, it is possible to isolate the trigonal 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]

Preparation

Anhydrous cadmium chloride can be prepared by the reaction of hydrochloric acid and cadmium metal or cadmium oxide.^[14]

Cd + 2 HCl → CdCl₂ + H₂

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 and chlorine 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]

Uses

Cadmium chloride is used for the preparation of cadmium sulfide, used as "cadmium yellow", a brilliant-yellow stable inorganic pigment.^[14]

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:^[16]

CdCl
₂ + 2 RMgX → R
₂Cd + MgCl
₂ + MgX
₂

R
₂Cd + 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.

Like all cadmium compounds, CdCl
₂ is highly toxic and appropriate safety precautions must be taken when handling it.

References

^ ^a ^b ^c ^d ^e ^f ^g Anatolievich, Kiper Ruslan. "cadmium chloride". chemister.ru. Retrieved 2014-06-25.
^ ^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.
^ ^a ^b Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). New York: D. Van Nostrand Company. p. 169.
^ ^a ^b ^c ^d "Cadmium Chloride - CdCl2". chem.uwimona.edu.jm. Mona, Jamaica: The University of the West Indies. Retrieved 2014-06-25.
^ ^a ^b ^c Sigma-Aldrich Co., Cadmium chloride. Retrieved on 2014-05-23.
^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0087". National Institute for Occupational Safety and Health (NIOSH).
^ "Cadmium compounds (as Cd)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
^ A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
^ ^a ^b H. Leligny; J. C. Monier (1974). "Structure cristalline de CdCl2.H2O" [Crystal structure of CdCl2.H2O]. Acta Crystallographica B (in French). 30 (2): 305–309. doi:10.1107/S056774087400272X.
^ ^a ^b H. Leligny; J. C. Monier (1975). "Structure de CdCl2.2,5H2O" [Structure of CdCl2.2,5H2O]. Acta Crystallographica B (in French). 31 (3): 728–732. doi:10.1107/S056774087500369X.
^ ^a ^b H. Leligny; J. C. Monier (1979). "Structure de dichlorure de cadmium tétrahydraté" [Structure of cadmium dichloride tetrahydrate]. Acta Crystallographica B (in French). 35 (3): 569–573. doi:10.1107/S0567740879004179.
^ 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.
^ ^a ^b ^c ^d Karl-Heinz Schulte-Schrepping; Magnus Piscator (2000). "Cadmium and Cadmium Compounds". Ullmann's Encyclopedia of Industrial Chemistry (6th ed.). p. 472. doi:10.1002/14356007.a04_499. ISBN 9783527306732.
^ 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.
^ J. March, Advanced Organic Chemistry, 4th ed., p. 723, Wiley, New York, 1992.