Just how resilient are biofilms?

Biofilms hold promise for generating electricity and removing contamination from groundwater, but they also threaten many industrial processes and human health. As the environment changes in which these biofilms thrive, it ...

A new 2-D magnet draws future devices closer

We are all familiar with the image of electrons zipping around an atom's nucleus and forming chemical bonds in molecules and materials. But what is less known is that electrons have an additional unique property: spin. It ...

Antioxidants protect cells from harmful water contaminant

Antioxidants such as vitamin C could help reduce harmful effects from hexavalent chromium, according to a new study performed with human cells. The contaminant, which is often produced by industrial processes, was featured ...

Strength in numbers for 3-D printing

Additive manufacturing, also called 3-D printing, is commonly used to build complex three-dimensional objects, layer by layer. A*STAR researchers have shown that the process can also help to make a high-performance alloy ...

Revealing the inner working of magnetic materials

Björn Alling, researcher in theoretical physics at Linköping University, has, together with his colleagues, completed the task given to him by the Swedish Research Council in the autumn of 2014: Find out what happens inside ...

Novel nano material for quantum electronics

An international team led by Assistant Professor Kasper Steen Pedersen, DTU Chemistry, has synthesized a novel nano material with electrical and magnetic properties making it suitable for future quantum computers and other ...

Widespread groundwater contamination risk from chromium

When Erin Brockovich sued a major utility company in the 1990s for contaminating drinking water with hexavalent chromium, a toxic and carcinogenic metal, national attention turned to California. Now researchers have determined ...

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Chromium

Chromium ( /ˈkroʊmiəm/ kroh-mee-əm) is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable. The name of the element is derived from the Greek word "chrōma" (χρώμα), meaning colour, because many of its compounds are intensely coloured. Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago to coat weapons such as bronze crossbow bolts and steel swords found at the Terracotta Army. It later came to the attention of the west when it was discovered by Louis Nicolas Vauquelin in the mineral crocoite (lead(II) chromate) in 1797. Crocoite was used as a pigment, and after the discovery that the mineral chromite also contains chromium, this latter mineral was used to produce pigments as well.

Chromium was regarded with great interest because of its high corrosion resistance and hardness. A major development was the discovery that steel could be made highly resistant to corrosion and discoloration by adding chromium to form stainless steel. This application, along with chrome plating (electroplating with chromium) are currently the highest-volume uses of the metal. Chromium and ferrochromium are produced from the single commercially viable ore, chromite, by silicothermic or aluminothermic reaction or by roasting and leaching processes.

Although trivalent chromium (Cr(III)) is required in trace amounts for sugar and lipid metabolism, few cases have been reported where its complete removal from the diet has caused chromium deficiency. In larger amounts and different forms chromium can be toxic and carcinogenic. The most prominent example of toxic chromium is hexavalent chromium (Cr(VI)). Abandoned chromium production sites often require environmental cleanup.

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