Cadmium chloride

Crystal structure
__ Cd 2+      __ Cl -
General
Surname	Cadmium chloride
other names	Cadmium (II) chloride Cadmium dichloride
Ratio formula	CdCl 2
Brief description	white, odorless solid
External identifiers / databases
CAS number 10108-64-2 7790-78-5 (hemipentahydrate) 35658-65-2 (monohydrate) 34330-64-8 (hydrate) EC number 233-296-7 ECHA InfoCard 100.030.256 PubChem 24947 ChemSpider 23035 Wikidata Q411840
properties
Molar mass	183,32 g · mol -1
Physical state	firmly
density	4.05 g cm −3
Melting point	568 ° C
boiling point	960 ° C
solubility	1400 g l −1 in water
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 350-340-360FD-330-301-372-410 P: 201-260-301 + 310-330-304 + 340-310-308 + 313-403 + 233
Authorization procedure under REACH	particularly worrying : carcinogenic, mutagenic, toxic for reproduction ( CMR ), serious effects on human health are considered likely
MAK	repealed as carcinogenic
Toxicological data	88 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cadmium chloride is a chemical compound of cadmium and is one of the chlorides . The colorless salt crystallizes in a characteristic trigonal crystal structure , which serves as a structure type for numerous other compounds.

Extraction and presentation

Anhydrous cadmium chloride can be obtained by reacting heated cadmium with chlorine gas .

${\displaystyle \mathrm {Cd\ +\ Cl_{2}\rightarrow \ CdCl_{2}} }$

Cadmium chloride can also be obtained by dissolving cadmium or cadmium carbonate in hydrochloric acid and crystallizing it. This creates a cadmium chloride hydrate that can be dehydrated with thionyl chloride .

${\displaystyle \mathrm {CdCO_{3}+2\ HCl\longrightarrow CdCl_{2}+\ H_{2}O+\ CO_{2}} }$

It is also possible to display it by reacting cadmium with hydrogen chloride at 450 ° C

${\displaystyle \mathrm {Cd+2\ HCl\longrightarrow CdCl_{2}+H_{2}} }$

or a solution of cadmium acetate in anhydrous acetic acid (or its mixture with acetic anhydride ) with acetyl chloride .

${\displaystyle \mathrm {Cd(CH_{3}CO_{2})_{2}+2\ CH_{3}COCl\longrightarrow CdCl_{2}+2\ (CH_{3}CO)_{2}O} }$

properties

Cadmium chloride forms colorless, hygroscopic and very water-soluble crystals. It crystallizes in a layer structure in the trigonal crystal system in the space group R 3 m (space group no. 166) with the lattice parameters a = 3.85 Å and c = 17.46 Å. This structure consists of a cubic close packing of chloride anions, in which the cadmium cations are arranged in the octahedral gaps every second layer (layer sequence ABCABC, coordination type = 6: 3). This means that the cadmium ions are octahedral surrounded by six chloride ions. Each chloride ion forms the tip of a trigonal pyramid with three cadmium ions as a base. The CdCl ₂ structure is often used as a reference structure. In this structure mainly transition metal chlorides such as manganese (II) chloride , iron (II) chloride or zinc chloride , but also magnesium chloride , zinc bromide and nickel (II) iodide crystallize .

use

Cadmium chloride solutions adsorb hydrogen sulfide . It is also used in electroplating , microscopy , photography and as a starting material for the production of cadmium pigments .

Cadmium chloride acts as a catalyst in Biginelli reactions for the production of 3,4-dihydropyrimidin-2 (1 H ) -ones.

safety instructions

Cadmium chloride is a very toxic and environmentally hazardous substance that can be carcinogenic , mutagenic and toxic to reproduction. In inhalable form, according to Appendix II, No. 6 of the German Ordinance on Hazardous Substances (GefStoffV), the substance is classified as a particularly dangerous carcinogenic substance and may only be manufactured or used in closed facilities. An acutely toxic effect consists of a strong irritant effect on the respiratory tract after inhalation of vapors or aerosols up to pulmonary edema . Chronic poisoning damages the kidneys , liver and lungs . The visual characteristic of cadmium poisoning is the formation of a yellow border on the necks of the teeth by sulfidic cadmium compounds. An LD ₅₀ of 88 mg / kg (oral, anhydrous cadmium chloride) is given for rats . In addition, it is extremely toxic to many aquatic organisms (bacteria, algae, crustaceans).

Individual evidence

1. ↑ ^{a b c d e f g} Data sheet cadmium chloride from AlfaAesar, accessed on August 29, 2010 ( PDF )(JavaScript required) . .
2. ↑ ^{a b c} Entry on cadmium chloride in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
3. ↑ Entry on Cadmium chloride in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers and / or distributors can expand the harmonized classification and labeling .
4. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on July 16, 2014.
5. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1490.
6. ↑ ^{a b} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 1040.
7. ^ DE Partin, M. O'Keeffe: The Structures and Crystal Chemistry of Magnesium Chloride and Cadmium Chloride. In: Journal of Solid State Chemistry . 1991, 95, pp. 176-183, doi : 10.1016 / 0022-4596 (91) 90387-W .
8. ↑ Erwin Riedel, Christoph Janiak: Inorganic Chemistry . 7th edition. 2007, de Gruyter, ISBN 978-3-11-018903-2 , p. 138.
9. ↑ cadmium chloride . In: Römpp Chemistry Lexicon . Thieme Verlag, as of March 2002.
10. ↑ A. Venkat Narsaiah, AK Basak, K. Nagaiah: Cadmium Chloride: An Efficient Catalyst for One-Pot Synthesis of 3,4-Dihydropyrimidin-2 (1H) -ones. In: Synthesis. 2004, 8, pp. 1253-1256, doi : 10.1055 / s-2004-822383 .
11. ↑ Hazardous Substances Ordinance (GefStoffV) - as of April 2017