5
B
Boron
10.811
Atomic Number: 5
Atomic Weight: 10.811
Melting Point: 2348 K (2075°C or 3767°F)
Boiling Point: 4273 K (4000°C or 7232°F)
Density: 2.37 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Semi-metal
Period Number: 2 Group Number: 13 Group Name: none
What's in a name? From the Arabic word Buraq and the Persian word Burah, which are both words for the material "borax."
Say what? Boron is pronounced as BO-ron.
History and Uses:
Boron was discovered by Joseph-Louis Gay-Lussac and Louis-Jaques Thénard, French chemists, and independently by Sir Humphry Davy, an English chemist, in 1808. They all isolated boron by combining boric acid (H3BO3) with potassium. Today, boron is obtained by heating borax (Na2B4O7·10H2O) with carbon, although other methods are used if high-purity boron is required.
Boron is used in pyrotechnics and flares to produce a green color. Boron has also been used in some rockets as an ignition source. Boron-10, one of the naturally occurring isotopes of boron, is a good absorber of neutrons and is used in the control rods of nuclear reactors, as a radiation shield and as a neutron detector. Boron filaments are used in the aerospace industry because of their high-strength and lightweight.
Boron forms several commercially important compounds. The most important boron compound is sodium borate pentahydrate (Na2B4O7·5H2O). Large amounts of this compound are used in the manufacture of fiberglass insulation and sodium perborate bleach. The second most important compound is boric acid (H3BO3), which is used to manufacture textile fiberglass and is used in cellulose insulation as a flame retardant. Sodium borate decahydrate (Na2B4O7·10H2O), better known as borax, is the third most important boron compound. Borax is used in laundry products and as a mild antiseptic. Borax is also a key ingredient in a substance known as Oobleck, a strange material 6th grade students experiment with while participating in Jefferson Lab's BEAMS program. Other boron compounds are used to make borosilicate glasses, enamels for covering steel and as a potential medicine for treating arthritis.
Estimated Crustal Abundance: 1.0×101 milligrams per kilogram
Estimated Oceanic Abundance: 4.44 milligrams per liter
Number of Stable Isotopes: 2 (View all isotope data)
Ionization Energy: 8.298 eV
Oxidation State: +3
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This page is maintained by Steve Gagnon.
