Cadmium chloride
Crystal structure | |||||||||||||||||||
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__ Cd 2+ __ Cl - | |||||||||||||||||||
General | |||||||||||||||||||
Surname | Cadmium chloride | ||||||||||||||||||
other names |
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Ratio formula | CdCl 2 | ||||||||||||||||||
Brief description |
white, odorless solid |
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External identifiers / databases | |||||||||||||||||||
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properties | |||||||||||||||||||
Molar mass | 183,32 g · mol -1 | ||||||||||||||||||
Physical state |
firmly |
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density |
4.05 g cm −3 |
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Melting point |
568 ° C |
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boiling point |
960 ° C |
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solubility |
1400 g l −1 in water |
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safety instructions | |||||||||||||||||||
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Authorization procedure under REACH |
particularly worrying : carcinogenic, mutagenic, toxic for reproduction ( CMR ), serious effects on human health are considered likely |
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MAK |
repealed as carcinogenic |
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Toxicological data | |||||||||||||||||||
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 .
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 .
It is also possible to display it by reacting cadmium with hydrogen chloride at 450 ° C
or a solution of cadmium acetate in anhydrous acetic acid (or its mixture with acetic anhydride ) with acetyl chloride .
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
- ↑ a b c d e f g Data sheet cadmium chloride from AlfaAesar, accessed on August 29, 2010 ( PDF )(JavaScript required) . .
- ↑ a b c Entry on cadmium chloride in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
- ↑ 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 .
- ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on July 16, 2014.
- ^ 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.
- ↑ 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.
- ^ 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 .
- ↑ Erwin Riedel, Christoph Janiak: Inorganic Chemistry . 7th edition. 2007, de Gruyter, ISBN 978-3-11-018903-2 , p. 138.
- ↑ cadmium chloride . In: Römpp Chemistry Lexicon . Thieme Verlag, as of March 2002.
- ↑ 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 .
- ↑ Hazardous Substances Ordinance (GefStoffV) - as of April 2017