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Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal.
Naturally occurring cobalt, Co, consists of a single stable isotope, 59 Co (thus, cobalt is a mononuclidic element). Twenty-eight radioisotopes have been characterized; the most stable are 60 Co with a half-life of 5.2714 years, 57 Co (271.811 days), 56 Co (77.236 days), and 58 Co (70.844 days). All other isotopes have half-lives of less than ...
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.
[citation needed] Over geological time scales, very few metals can resist natural weathering processes like oxidation, so mainly the less reactive metals such as gold and platinum are found as native metals. The others usually occur as isolated pockets where a natural chemical process reduces a common compound or ore of the metal, leaving the ...
In humans most cobalt is found in Vitamin B12.A cobalt atom is visible in the center in this diagram. Cobalt is essential to the metabolism of all animals.It is a key constituent of cobalamin, also known as vitamin B 12, the primary biological reservoir of cobalt as an ultratrace element.
Francium-223, the only naturally occurring isotope of francium, [57] [58] is the product of the alpha decay of actinium-227 and can be found in trace amounts in uranium minerals. [59] In a given sample of uranium, there is estimated to be only one francium atom for every 10 18 uranium atoms.
The nuclides found naturally comprise not only the 286 primordials, but also include about 52 more short-lived isotopes (defined by a half-life less than 100 million years, too short to have survived from the formation of the Earth) that are daughters of primordial isotopes (such as radium from uranium); or else are made by energetic natural ...
Cobalt-60 (60 Co) is a ... 60 Co does not occur naturally on Earth in significant amounts, ... Cobalt is found in steel.