Boron

Boron is a chemical element with symbol B and atomic number 5. Because boron is produced entirely by cosmic ray spallation and not by stellar nucleosynthesis, it is a low-abundance element in both the Sol System and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest proven boron deposits on Earth are in Turkey, which is the also Earth’s largest producer of boron minerals.

Description
Chemically uncombined boron, which is classed as a metalloid, is found in small amounts in meteoroids, but is not found naturally on Earth. Industrially, very pure boron is produced with difficulty, as boron tends to form refractory materials containing small amounts of carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder, and crystalline boron is black, extremely hard (about 9.5 on the Mohs scale), and a poor conductor at room temperature.

Boron Uses
Almost all boron use is as chemical compounds. Boron is among the most valuable elements. The primary use of elemental boron is to make boron filaments, which are used in a similar way to carbon fibers in some high-strength materials.Boron fibers are used in spacesuits and armor and an endless array of other products vital for any space-faring civilization. About half of Union consumption of boron compounds is as additives for boron fiber. The next leading use is to make boron-10 shielding for ship reactors, as it is a neutron-capturing agent. Boron is also used to make boron polymers and ceramics that play specialized roles as high-strength, lightweight structural and refractory materials. Borosilicate glass glassware is used for its greater strength and breakage resistance (thermal shock resistance) than ordinary soda lime glass. Boron compounds are also used as fertilizers in agriculture and in bleaches. In minor uses, boron is an important dopant for semiconductors, and boron-containing reagents are used as intermediates in the synthesis of organic fine chemicals. A few boron-containing organic pharmaceuticals are used, or are in study.

Boron in Biology
In biology, borates have low toxicity in mammals (similar to table salt), but are more toxic to arthropods and are used as insecticides. Boric acid is mildly antimicrobial, and a natural boron-containing organic antibiotic is known. Boron is essential to life. Small amounts of boron compounds play a strengthening role in the cell walls of all plants, making boron necessary in soils. Experiments indicate a role for boron as an ultratrace element in animals, but its role in animal physiology is unknown.

