Boron is the first element in Group 13 of the periodic table. It is the only element in this chemical family that is not a metal. Its atomic number if 5, its atomic mass is 10.811, and its chemical symbol is B.

Properties

Boron exists in at least three distinct allotropic forms. One consists of clear red crystals with a density of 2.46 grams per cubic centimeter. A second allotrope consists of black crystals with a metallic appearance and a density of 2.31 grams per cubic centimeter. A third allotrope occurs as an amorphous brown powder with a density of 2.350 grams per cubic centimeter. All allotropes of boron have very high melting points, from 4,000-4,200°F (2,200-2,300°C).

One property of special interest is boron's ability to absorb neutrons in abundant amounts. This property is utilized in control rods of nuclear reactors, which regulate the number of free neutrons passing through...