Chromium is mined as chromite (FeCr2O4) ore. Chromium is obtained commercially by heating the ore in the presence of aluminium or silicon. Roughly half the chromite ore in the world is produced in South Africa. Kazakhstan, India and Turkey are also substantial producers. Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan and southern Africa. Approximately 15 million tons of marketable chromite ore were produced in 2000, and converted into approximately 4 million tons of ferro-chrome with an approximate ...

See also:

Chromium, Chromium - Notable characteristics, Chromium - Applications, Chromium - History, Chromium - Biological role, Chromium - Occurrence, Chromium - Compounds, Chromium - Isotopes, Chromium - Chromium and the quintuple bond, Chromium - Precautions

Read more here: » Chromium: Encyclopedia II - Chromium - Occurrence

Because of its role as a scaling factor, Avogadro's number provides the link between a number of useful physical constants when we move between an atomic mass scale and a kilogram (SI) scale. For example, it provides the relationship between: the universal gas constant R and the Boltzmann constant kB: R = kB NA the Faraday constant F an ...

See also:

Avogadro's number, Avogadro's number - History, Avogadro's number - Application, Avogadro's number - Physical significance of Avogadro's number, Avogadro's number - Additional physical relations, Avogadro's number - Numerical value, Avogadro's number - Connection to masses of protons and neutrons, Avogadro's number - Avogadro's number in life

Read more here: » Avogadro's number: Encyclopedia II - Avogadro's number - Additional physical relations

Californium was first synthesized by University of California, Berkeley researchers Stanely Thompson, Kenneth Street, Jr., Albert Ghiorso and Glenn T. Seaborg in 1950. It was the sixth transuranium element to be discovered and the team announced their discovery on March 17, 1950. It was named after the U.S. state of California and for the University of California system. To produce element 98, the team bombarded a microgram-sized target of curium-242 with 35 MeV alpha particles in the 60-inch Berkeley cyclotron which produced atoms of californium-245 (ha ...

See also:

Californium, Californium - Notable characteristics, Californium - History, Californium - Isotopes

Read more here: » Californium: Encyclopedia II - Californium - History

In 1761, Johann Gottlob Lehmann found an orange-red mineral in the Ural Mountains which he named Siberian red lead. Though misidentified as a lead compound with selenium and iron components, the material was in fact lead chromate (PbCrO4), now known as the mineral crocoite. In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red "lead" mineral that had very useful properties as a pigment in paints. The use of Siberian red lead as a paint pigment developed rapidly. A bright yellow made from croco ...

See also:

Chromium, Chromium - Notable characteristics, Chromium - Applications, Chromium - History, Chromium - Biological role, Chromium - Occurrence, Chromium - Compounds, Chromium - Isotopes, Chromium - Chromium and the quintuple bond, Chromium - Precautions

Read more here: » Chromium: Encyclopedia II - Chromium - History

In models of the Big Bang, Big Bang nucleosynthesis predicts that within one to three minutes of the Big Bang all the current atomic material in the universe was created producing no heavier element than lithium, but mostly hydrogen and helium. However, although the basic atomic particles of matter were created, atoms themselves could not form in the intense heat. Big Bang chronology of the atom continues to approximately 379,000 years after the Big Bang when the cosmic temperature had dropped to just 3,000 K which allowed the first a ...

See also:

Atom, Atom - Properties of the atom, Atom - Subatomic particles, Atom - Atomic forces, Atom - Atom size and speed, Atom - Elements isotopes and ions, Atom - Valence and bonding, Atom - Atomic spectrum, Atom - Atoms and antimatter, Atom - Atoms and the Big Bang, Atom - History of atomic theory, Atom - Study of atoms

Read more here: » Atom: Encyclopedia II - Atom - Atoms and the Big Bang

Democritus and Leucippus, Greek philosophers in the 5th century BC, presented the first theory of atoms (see article atomism for more details). The Greeks believed that atoms were all made of the same material but had different shapes and sizes, which determined the physical properties of the material. For instance, the atoms of a liquid were thought to be smooth, allowing them to slide over each other. This theory was not founded on experimental evidence. In 1808, John Dalton proposed that an element is composed of a single, unique t ...

See also:

Atom, Atom - Properties of the atom, Atom - Subatomic particles, Atom - Atomic forces, Atom - Atom size and speed, Atom - Elements isotopes and ions, Atom - Valence and bonding, Atom - Atomic spectrum, Atom - Atoms and antimatter, Atom - Atoms and the Big Bang, Atom - History of atomic theory, Atom - Study of atoms

Read more here: » Atom: Encyclopedia II - Atom - History of atomic theory

Potassium permanganate, also called Condy's crystals, is a commonly used laboratory reagent because of its oxidizing properties and finds use as a topical medicine (for example, in the treatment of fish diseases). Manganese(IV) oxide (manganese dioxide) is used in dry cells, and can be used to decolorize glass that is polluted by trace amounts of iron. Manganese compounds can color glass an amethyst color, and are responsible for the color of true amethyst. Manganese dioxide is also used in the manufacture of oxygen an ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Compounds

Naturally occurring manganese is composed of 1 stable isotope; 55-Mn. 18 radioisotopes have been characterized with the most stable being 53-Mn with a half-life of 3.7 million years, 54-Mn with a half-life of 312.3 days, and 52-Mn with a half-life of 5.591 day s. All of the re maining radioactive isotopes have half lives that are less than 3 hours and the majority of these have half lives that are less than 1 minute ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Isotopes

Manganese in excess is toxic. Exposure to manganese dusts and fumes should not exceed the ceiling value of 5 mg/m3 for even short periods because of its toxicity level. Acidic permanganate so lutions will oxidize any organic material they come into contact with. The oxidation process can generate enough heat to ignite some organic substances. In 2005, a study suggested a possible link between manganese inhalation and central nervous system toxicity in rats. It is hypothesized that long-term exposure to the naturally-occurring manganese in shower water ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Precautions

Managanese is much too reactive to be found in nature in the uncombined state. However, compounds of manganese are so abundant that the element ranks ninth in abundance among metallic elements in the Earth's crust. By mass, manganese constitutes about 0.11 percent of the earth's crust. However, to be profitably mined, manganese ores must have a content of at least 25 percent manganese. Manganese occurs principally as pyrolusite (MnO2), and to a lesser extent as rhodochrosite (MnCO3). Land-based resources are larg ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Occurrence

Manganese is an essential trace nutrient in all forms of life. It plays a very important role in photosynthesis in plants and algae. The classes of enzymes that have manganese cofactors are very broad and include such classes as oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins. The best known manganese-containing polypeptides may be arginase, Mn-containing su ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Biological role

Because of their ubiquitous nature, atoms have been an important field of study for many centuries. Current specific research areas include: the physics of ultra-cold atoms and molecules, including Bose-Einstein condensation, creation of more accurate and precise atomic clocks, collisions involving highly excited states of atoms and molecules including Rydberg states, low-energy elastic and threshold inelastic scattering of charged particles, the search for dark matter, the search for a grand unified quantum theory of gravity, and the study of atoms ...

See also:

Atom, Atom - Properties of the atom, Atom - Subatomic particles, Atom - Atomic forces, Atom - Atom size and speed, Atom - Elements isotopes and ions, Atom - Valence and bonding, Atom - Atomic spectrum, Atom - Atoms and antimatter, Atom - Atoms and the Big Bang, Atom - History of atomic theory, Atom - Study of atoms

Read more here: » Atom: Encyclopedia II - Atom - Study of atoms

Manganese is essential to iron and steel production by virtue of its sulfur-fixing, deoxidizing, and alloying properties. Steelmaking, including its ironmaking component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand. Among a variety of other uses, manganese is a key component of low-cost stainless steel formulations and certain widely used aluminium alloys. It is also added to gasoline in order to reduce engine knocking. Manganese(IV) oxide (manganese dioxide) is used in the original type ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - Applications

Manganese (Latin magnes, meaning "magnet") was in use in prehistoric times; paints that were pigmented with manganese dioxide can be traced back 17,000 years. The Egyptians and Romans used manganese compounds in glass-making, to either remove color from glass or add color to it. Manganese can be found in the iron ores used by the Spartans. Some speculate that the exceptional hardness of Spartan st eels derives from the inadvertent p ...

See also:

Manganese, Manganese - Notable characteristics, Manganese - Applications, Manganese - History, Manganese - Biological role, Manganese - Occurrence, Manganese - Compounds, Manganese - Isotopes, Manganese - Precautions, Manganese - External l inks

Read more here: » Manganese: Encyclopedia II - Manganese - History

About 65 percent of the nickel consumed in the Western World is used to make austenitic stainless steel. Another 12 percent goes into superalloys. The remaining 23% of consumption is divided between alloy steels, rechargeable batteries, catalysts and other chemicals, coinage, foundry products, and plating. The five-cent Canadian and US coin is only 25% nickel. The largest consumer of nickel is Japan, which uses 169,600 tonnes per year (2005) See also:

Nickel, Nickel - Notable characteristics, Nickel - Applications, Nickel - History, Nickel - Biological role, Nickel - Occurrence, Nickel - Extraction and Purification, Nickel - Compounds, Nickel - Isotopes, Nickel - Precautions, Nickel - Notes

Read more here: » Nickel: Encyclopedia II - Nickel - Applications