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Glossary
Boron (B)
Boron is a metalloid element with the chemical symbol B and atomic number 5. It occupies a unique position on the periodic table—situated between metals and nonmetals—and displays properties of both. Boron is hard, brittle, and black in its pure crystalline form, yet it can also exist as an amorphous brown powder. It is chemically reactive at high temperatures and forms compounds that are vital in industry, metallurgy, materials science, and even biology.
In nature, boron is never found in its pure elemental state. Instead, it occurs in borate minerals such as borax (Na₂B₄O₇·10H₂O), kernite, and ulexite, which are commonly mined in dry lake beds and arid regions—most notably in Turkey, the U.S. (California), and South America. These minerals are the primary source for industrial boron compounds.
Boron’s chemical versatility stems from its ability to form strong covalent bonds and complex molecular structures, including borates, borides, and boranes. One of its defining features is its electron deficiency, which allows it to form compounds with unusual bonding arrangements, making it an important element in high-performance materials.
In practical use, boron and its compounds play major roles across industries. Boron oxide (B₂O₃) is a key ingredient in borosilicate glass, known for its heat and chemical resistance (used in Pyrex®). Boron carbide (B₄C) and titanium diboride (TiB₂) are superhard materials used in armor plating and cutting tools. Sodium borates are widely used in detergents, fertilizers, and flame retardants. In metallurgy, boron is added in trace amounts to steels and alloys to improve hardness, wear resistance, and grain structure.
Boron is also crucial in electronics and energy. It acts as a semiconductor dopant, especially in silicon-based devices, and plays a role in nuclear reactors as a neutron absorber due to the high neutron cross-section of the isotope boron-10. Additionally, in agriculture, boron is an essential micronutrient for plants, aiding in cell wall formation and sugar transport.
