| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 1,518,598,242 visitors served. |
|
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
chromium |
Also found in: Encyclopedia, Wikipedia, Hutchinson | 0.09 sec. |
|
chromium /chro·mi·um/ (Cr) (kro´me-um) a chemical element, at. no. 24. It is an essential dietary trace element, but hexavalent chromium is carcinogenic. chromium 51 a radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture with emission of gamma rays (0.32 MeV); it is used to label red blood cells for measurement of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival. chromium trioxide chromic acid.
chromium (Cr) [krō′mē·əm] Etymology: Gk, chroma, color a hard, brittle metallic element. Its atomic number is 24; its atomic mass is 51.99. It does not occur naturally in pure form but exists in combination with iron and oxygen in chromite, a mineral found chiefly in Africa, Albania, Russia, and Turkey. Chromium strongly resists corrosion and is used extensively to plate other metals, harden steel, and, in combination with other elements, form colored compounds. Stainless steels are more than 10% chromium and strongly resist rusting. Traces of chromium occur in plants and animals, and there is evidence that this element may be important in human nutrition, especially in carbohydrate metabolism. Some experts estimate that the safe and adequate daily intake of chromium ranges from 0.1 to 0.2 mg, depending on the age of the individual. Workers in chromite mines are susceptible to pneumoconiosis caused by the inhalation of chromite dust particles that lodge in the lung. Chromate salts have been identified as potential carcinogens. Chromium 51 isotope is used in blood studies. chromium, n an essential mineral that is associated with glucose tolerance, high cholesterol, blocked arteries, glaucoma, obesity, diabetes, and hypoglycemia. Not for use by chil-dren or pregnant or nursing women. Also called chromium picolinate, chromium polynicotinate, or chromium chloride. chromatography, n any one of several processes for separating and analyzing various gaseous or dissolved chemical materials according to differences in their absorbency with respect to a specific substance. chromium, (Cr), n a hard, brittle, metallic element with an atomic number of 24 and an atomic weight of 51.996. Chromium strongly resists corrosion and is used extensively to plate other metals and as an alloy to harden steel. Stainless steels are more than 10% chromium. chromium a chemical element, atomic number 24, atomic weight 51.996, symbol Cr. See Table 6. chromium-51 chromium nutritional deficiency possibly causally related to the onset of diabetes mellitus in primates. chromium trioxide possibly carcinogenic in humans. See also chromate. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
| ? Mentioned in | ? References in periodicals archive | |
|---|---|---|
workers and several million more worldwide are exposed to Cr(VI) in the workplace, where chromium compounds (or chromates) serve as anticorrosion agents in protective coatings, as pigments in paints and plastics, and in chrome plating on tools, aircraft engine components, railroad wheel bearings, and automobile parts. Hexavalent chromium compounds are widely used in the industry as ingredients and catalysts in pigments, metal plating and chemical synthesis. Louis Bay, would be likely to accumulate in oysters near the bay than in sediments because soluble chromium compounds would be expected to precipitate or complex with fine particles that are ingested by filter-feeding oysters. |
| Medical Dictionary |
| Free Tools: |
For surfers:
Browser extension |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|---|