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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 toxicity refers to any poisonous toxic effect in an organism or cell that results from exposure to specific forms of chromium—especially hexavalent chromium. [1] Hexavalent chromium and its compounds are toxic when inhaled or ingested. Trivalent chromium is a trace mineral that is essential to human nutrition.
Chromium, especially hexavalent chromium, is highly toxic to fish because it is easily absorbed across the gills, readily enters blood circulation, crosses cell membranes and bioconcentrates up the food chain. In contrast, the toxicity of trivalent chromium is very low, attributed to poor membrane permeability and little biomagnification. [141]
PG&E used chromium 6, or hexavalent chromium (a cheap and efficient rust suppressor), in its compressor station for natural-gas transmission pipelines. [1] [3] Hexavalent-chromium compounds are genotoxic carcinogens. In 1993, legal clerk Erin Brockovich began an investigation into the health impacts of the contamination. A class-action lawsuit ...
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]
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 ...
Chromium trioxide (also known as chromium(VI) oxide or chromic anhydride) is an inorganic compound with the formula CrO 3. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. [6] This compound is a dark-purple solid under anhydrous conditions and bright orange when wet. The substance dissolves in water ...
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]