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Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) is any chemical compound that contains the element chromium in the +6 oxidation state (thus hexavalent). [1] It has been identified as carcinogenic, which is of concern since approximately 136,000 tonnes (150,000 tons) of hexavalent chromium were produced in 1985. [ 2 ]
Chromium trioxide is highly toxic, corrosive, and carcinogenic. [12] It is the main example of hexavalent chromium , an environmental hazard . [ 13 ] The related chromium(III) derivatives are not particularly dangerous; thus, reductants are used to destroy chromium(VI) samples.
For example, in the coating formed on aluminum by a commercial bath, about 23% of the chromium atoms were found to be hexavalent Cr 6+ , except in a region close to the metal. These chromium(VI) residues can migrate when the coating is wetted, and are believed to play a role in preventing corrosion in the finished part—specifically, by ...
Hexavalent chromium compounds (including chromium trioxide, chromic acids, chromates, chlorochromates) are toxic and carcinogenic. Chromium trioxide and chromic acids are strong oxidizers and may react violently if mixed with easily oxidizable organic substances. Chromic acid burns are treated with a dilute sodium thiosulfate solution. [18]
Potassium dichromate, K 2 Cr 2 O 7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health.
In this compound, as in all chromates and dichromates, chromium is in a +6 oxidation state, commonly known as hexavalent chromium. It is a salt consisting of ammonium ions and dichromate ions. Ammonium dichromate is sometimes known as Vesuvian Fire , because of its use in demonstrations of tabletop "volcanoes". [ 2 ]
Chromium(III) chloride (also called chromic chloride) is an inorganic chemical compound with the chemical formula Cr Cl 3. It forms several hydrates with the formula CrCl 3 · n H 2 O , among which are hydrates where n can be 5 (chromium(III) chloride pentahydrate CrCl 3 ·5H 2 O ) or 6 (chromium(III) chloride hexahydrate CrCl 3 ·6H 2 O ).
Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. [3] [4]