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Chromium is the 21st most abundant element in Earth's crust [41] with an average concentration of 100 ppm. Chromium compounds are found in the environment from the erosion of chromium-containing rocks, and can be redistributed by volcanic eruptions.
A native metal is any metal that is found pure in its metallic form in nature. [1] [2] Metals that can be found as native ... Native chromium has been found in ...
Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry.
Soluble hexavalent chromium is the most common type of chromium in oceans, where over 70% of dissolved chromium in the ocean is found in oxyanions such as chromate (CrO 2− 4). Soluble trivalent chromium is also found in the oceans where complexation with organic ligands occurs. Chromium is estimated to have a residence time of
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
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 ]
The FDA’s analysis found chromium levels of 0.590 parts per million in one sample and 0.566 ppm in another. Dr. Laura Breeher, ...
Chromium-51 is a synthetic 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.