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Known for its silver medal , glistening appearance , chromium is used to coat cars , stove and other appliances to protect them from corrosion and to improve their looks . Chromium ’s gamey melting item and static structure also make it useful in the material and refractory manufacture . When fuse with other factor , chromium makes vibrant gloss and is used as a dyestuff , which is what originally earned it its name from the Greek wordchromafor " people of colour . "
It is of course base in compound in the earth ’s crust . However , consuming high levels of chromium in contaminated drinking water or inhaling exhaust of the het factor can do ulcers , cancer and other health problems .
Chromite ore is the main source of pure chromium.
Just the facts
Discovery of chromium
French chemist Louis Nicolas Vauquelin first isolated chromium from a bright scarlet mineral call Siberian red lead , now experience as lead chromate ( PbCrO4 ) in 1797 . concord to John Emsley in his book , " Nature ’s Building Blocks : An A - ezed Guide to the Elements " ( Oxford University Press , 1999 ) , it took Vauquelin a twelvemonth before he was able to come down out the lead and obtain pure Cr . He mixed the atomic number 24 in a variety of solutions and was intrigued by the many coloring it bring forth , thereby naming the element after the Hellenic wordchromameaning " color . "
Sources of chromium
Chromium is the 21st most common element set up in the Earth ’s crust , but it is not find in its devoid metal configuration . Instead , it is in the main found in chromite ore , according to Robert E. Krebs in his Word , " The History and Use of Our Earth ’s Chemical Elements : A Reference Guide " ( Greenwood Publishing Group , 2006 ) . Chromite is mined in Zimbabwe , Russia , New Zealand , Turkey , Iran , Albania , Finland , the Philippines and Madagascar . About 20,000 tons of chromium metal are produced each class , and there are still about a billion gobs of unexploited deposit in Greenland , Canada , and the United States , consort to Emsley . Chromium metal is then obtain by heating the chromite ore in the bearing of aluminium or silicon , allot tothe Jefferson Lab .
Properties of chromium
Cr is atransition metal in Group 6 on the Periodic Table of Elements . In its pure var. , chromium is a silver , lustrous , laborious alloy that has a high refinement , idealistic for electroplating .
The most crucial Cr compounds are the chromate of Na and potassium , the dichromates , and atomic number 19 and ammonium chrome alums , accord to theLos Alamos National Laboratory . Chromium compounds are toxic and should be handled with concern .
Chromium compound are all vividly colored and are used as pigments — hopeful green , chicken , crimson and orange . Rubies are blood-red because of chromium , and glass process with chromium has an emerald light-green color , according to theRoyal Society of Chemistry(RSC ) .
Used for protection and beauty
Using a proficiency call electroplating , a thin level of chromium can coat metal and charge card object , include car part and household contrivance , to give a shiny , attractive destination . For example , automotive decorator use chrome brim and wheels to smarten up up their cars . Chrome plating is not only used for looks ; because the chromium forms a protective oxide layer on the surface , chrome - plated objects protest erosion , according to Krebs .
unsullied steel is an admixture of iron and at least 10.5 percent chromium . It is extremely resistant to erosion . It is used in kitchen cutter , convenience and cooking utensil such as unstained steel pans and skillets .
About 90 percent of leather is chrome bronze , according to Emsley . During this cognitive process , chromium sulfate is used to address beast skin and turn it into leather that is resistant to hot water that can cause degradation .
Kilns and furnaces apply bricks made of chromite ore , which retain strength at high temperatures . The cloth industry uses chromium ions to help adhere dyes to cloth . Chromium ’s mellow thaw point , moderate thermal expansion and crystalline structure stability make it worthy for these purposes .
Dangerous in excess
Though its specific office in humans is unclear , studies have shown that atomic number 24 is an essential trace element that is launch in RNA and helps the body to use glucose . Chromium is most concentrated in the placenta , and its presence in the body decreases with age .
A safe amount is about 1 mg per day , according to the RSC . food such as brewer ’s yeast , wheat germ and kidney are robust in chromium . However , it is poisonous in surfeit .
In the 2000 photographic film " Erin Brockovich , " Julia Roberts portrays an environmental activist and legal clerk who lead a case against a gas and electric fellowship for contaminating drunkenness H2O with chromium(VI ) , a toxic compoundknown to cause Crab , according to the U.S. Occupational Safety and Health Administration ( OSHA ) . Though Brockovich win the casing in existent life and in the movie , scientists have criticizedher lack of grounds evidence that chromium(VI ) , and not other factors , was the cause of the numerous wellness issues include cancer in the residential area of Hinkley , Calif. However , several studies in the preceding few year havelinked chromium(VI ) in water tap water to cancerand the EPA has localize a drunkenness piss concentration limit for the component to protect public wellness .
undue exposure to atomic number 24 can also induce chrome ulcers , particularly when process with it for months while chrome - metal plating or leather lashing , harmonise to Emsley . Chrome ulcers are fidgety and raw holes in the skin or the tummy . If dust comprise chromium is inhaled , industrial workers are more prone to ulcers in the nasal cavity and lung Crab . to boot , a2017 report published in European Journal of Clinical Nutritionlinked high levels of urinary chromium to cardiovascular disease and diabetes .
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