All practice pages/Interatomic theory/Elements
Element 5, a metalloid
A hard black metalloid that plants need, heat-proof glass depends on, and the strongest permanent magnets contain.
Period 2, group 13. The other metalloids are tinted, and every cell opens its own article.
Three valence electrons. Boron is too small and holds its electrons too tightly to form B³⁺ ions, so it shares electrons in covalent bonds, often ending up with only six electrons around it instead of eight.
Never free in nature. It is mined as borate minerals such as borax and kernite, mostly in Turkey and in the Mojave Desert town of Boron, California. Plants need a trace of it to grow.
Joseph Louis Gay-Lussac and Louis Jacques Thénard, and separately Humphry Davy, isolated impure boron in 1808. The name joins borax, from the Arabic buraq, with the ending of carbon, which boron resembles.
Borosilicate glass, the heat-resistant kind in lab glassware and oven dishes, uses a large share. Borax goes into detergents and homemade slime, and boric acid is a mild antiseptic and insecticide. Boron carbide is among the hardest materials made and goes into body armor. Boron-10 absorbs neutrons, so it helps control nuclear reactors, and boron is part of the neodymium magnets in motors and headphones.