A chemical element with symbol Cr and atomic number 24.
Properties of chromium. Chromium is a transition metal in Group 6 on the Periodic Table of Elements. In its pure form, chromium is a steel-gray, lustrous hard metal that has a high polish. It has many compounds that are all colored. [See Periodic Table of the Elements ]. Of the compounds, the most important are the chromates of sodium and potassium; the dichromates; and potassium and ammonium chrome alums.  Chromium is an essential trace element for humans because it helps us to use glucose. However, it is poisonous in excess. We take in about 1 milligram a day. Foods such as brewer’s yeast, wheat germ and kidney are rich in chromium.  Chromium was discovered as an element after it came to the attention of the Western world in the red crystalline mineral crocoite (lead(II) chromate), discovered in 1761 and initially used as a pigment. Louis Nicolas Vauquelin first isolated chromium metal from this mineral in 1797. Trivalent chromium (Cr(III)) ion is possibly required in trace amounts for sugar and lipid metabolism, although the issue remains in debate. In larger amounts and in different forms, chromium can be toxic and carcinogenic. Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point. Trivalent chromium (Cr(III)) ion is possibly required in trace amounts for sugar and lipid metabolism, although the issue remains in debate. In larger amounts and in different forms, chromium can be toxic and carcinogenic. 1 It is the first element in Group 6 on the Periodic Table. 2  Chromium is a hard, lustrous, steel-gray metal. 3  Stainless steel is hard and resists corrosion due to the addition of chromium. 4  Chromium is the only element which shows antiferromagnetic ordering in its solid state at and below room temperature.  Chromium is the first element in the sixth column of the periodic table. It is classified as a transition metal. Chromium atoms have 24 electrons and 24 protons with the most abundant isotope having 28 neutrons.  Chromium around us. Chromium is an essential trace element and has a role in glucose metabolism. It seems to have an effect in the action of insulin. In anything other than trace amounts, chromium compounds should be regarded as highly toxic. Chromium is not found as the free metal in nature. The most important ore is chromite (FeCr 2 O 4) and this is found in Turkey, USA, South Africa, Albania, Finland, Iran, Madagascar, Russia, Southern Rhodesia, Transvaal, Cuba, Brazil, Japan, India, Pakistan, and the Philippines. Chromium is steel-gray, lustrous, hard, metallic, and takes a high polish. Its compounds are toxic. It is found as chromite ore. Siberian red lead (crocoite, PrCrO 4) is a chromium ore prized as a red pigment for oil paints. Hexavalent chromium [Cr(VI)] is one of the valence states (+6) of the element chromium. It is usually produced by an industrial process. Cr(VI) is known to cause cancer. In addition, it targets the respiratory system, kidneys, liver, skin and eyes.  Chromium is a mineral our bodies use in small amounts for normal body functions, such as digesting food. Chromium exists in many natural foods including brewer's yeast, meats, potatoes (especially the skins), cheeses, molasses, spices, whole-grain breads and cereals, and fresh fruits and vegetables. Chromium helps to move blood sugar (glucose) from the bloodstream into the cells to be used as energy and to turn fats, carbohydrates, and proteins into energy. 1  Chromium may help some people with type 2 diabetes. 2  It may help them control their blood sugar and may play a role in the management of type 2 diabetes.
http://www.livescience.com/29194-chromium.html http://www.rsc.org/periodic-table/element/24/chromium https://en.wikipedia.org/wiki/Chromium https://en.wikipedia.org/wiki/Chromium http://chemistry.about.com/od/chromium/a/10-Chromium-Facts.htm http://www.ducksters.com/science/chemistry/chromium.php http://www.webelements.com/chromium/ https://www.osha.gov/SLTC/hexavalentchromium/ http://www.webmd.com/digestive-disorders/tc/chromium-topic-overview
what is the element chromium