Atomic Number: 5
Atomic Symbol: B
Atomic Weight: 10.811
Melting Point: 3,767 F (2,075 C)
Boiling Point: 7,232 F (4,000 C)
[See Periodic Table of the Elements]
Word origin: Boron is derived from the Arabic word buraq as well as the Persian word burah. Both are words for the mineral borax.
Discovery: Compounds of boron have been known for thousands of years, but the element was not discovered until 1808 when Sir Humphry Davy, in England, and Joseph-Louis Gay-Lussac and Louis-Jacques Thénard, in France, independently isolated it.
Properties of boron
Boron does not occur naturally on Earth, but does occur as orthoboric acid and is typically found in certain volcanic spring waters and as borates in boron and colemantie. The isotopes boron-10 and boron-11 do occur naturally.
Boron has a capacity to form stable covalently bonded molecular networks, making it similar to carbon. Thousands of compounds are formed by thousands of families, including carbonates, metalloboranes, phosphacarboranes.
Boron nitride also behaves like an electrical insulator but conducts heat like a metal. Boron is a good electrical conductor at high temperatures but a poor conductor of electricity at room temperatures.
While some of the more exotic boron hydrogen compounds are toxic and do require special care, elemental boron and the borates are not considered toxic, and they do not require special handling.
The element’s optical characteristics include transmitting portions of the infrared.
Sources of boron
Ore rasorite (kernite) and tincal (borax ore) are both important sources of boron and are found in the Mojave Desert. Turkey, Argentina, Bolivia and Chile also have extensive deposits of boron and borax.
A brownish-black powder, known as impure or amorphous boron, can be produced by heating boron trioxide with magnesium powder. Amorphous boron is used in pyrotechnic flares to provide a distinctive green color and in rockets as an igniter.
Boron that is 99.9999 percent pure has been produced commercially.
Uses of boron
Sodium borax pentahydrate is used in massive quantities in the manufacture of insulation fiberglass and sodium perborate bleach, making it the most commercially important boron compound in terms of dollar sales.
Textile production relies on boric acid, which is also an important boron compound with major markets in textile products. Boron compounds are also widely used in the production of borosilicate glasses.
Sodium borate decahydrate, better known as borax, is used in laundry products and as a mild antiseptic. Other boron compounds show promise in treating arthritis.
Because boron has lubricating properties similar to graphite, and the hydrides are easily oxidized with considerable energy liberation, its potential as a rocket fuel has been studied. Boron filaments are a high-strength, lightweight material primarily used for advanced aerospace structures.
The isotope boron-10 is used as a control for nuclear reactors and as a shield for nuclear radiation, and in instruments used for detecting neutrons.
Boron nitride can be used to make a material as hard as diamond.
(Source: Los Alamos National Laboratory)