Boron
Definition and meaning of Boron in chemistry.
![Boron element card: symbol B, atomic number 5, atomic mass 10.81, electron configuration [He] 2s² 2p¹, oxidation states +3, Metalloid, group 13, period 2, solid at room temperature.](/assets/images/terms/boron-chemical-element.webp)
Boron is a rare chemical element with the symbol B and atomic number 5. It is a versatile metalloid that never exists as a free, pure element in nature. Instead, it naturally combines with oxygen to form various stable minerals called borates.
In more detail
Boron sits in group 13 of the periodic table as a unique metalloid. A metalloid is an element that shares physical properties with both metals and nonmetals. Boron exists in several distinct forms, which scientists call allotropes.
Amorphous boron appears as a fine brown powder, while crystalline boron is a hard, black, brittle solid. Chemically, boron has only three outer valence electrons available for making chemical bonds. It tends to form covalent bonds to share its electrons with other atoms.
This sharing behavior creates complex, three-dimensional network structures instead of simple ionic compounds. Many students incorrectly assume that boron behaves like a typical metal since it is near aluminum. However, its small atomic size makes it behave more like carbon or silicon.
We find boron in dried desert lakes as minerals like borax and kernite. People use borax compounds in household cleaning products, laundry boosters, and pest control formulas. It is also an essential nutrient that helps plants build strong, rigid cell walls.
In addition, the special boron-10 isotope can absorb free neutrons without splitting apart. This rare property makes it very useful for control rods that regulate nuclear reactors.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | B |
| Atomic number | 5 |
| Atomic mass | 10.81 u |
| Category | Metalloid |
| Discovery year | 1808 |
| State at STP | Solid |
Manufacturers mix boron into molten silica to produce durable borosilicate glass. This special glass resists thermal shock, which means it will not crack when the temperature changes suddenly. The presence of boron lowers the thermal expansion rate of the glass structure significantly. Because of this property, scientists use it to make laboratory beakers, kitchen cookware, and high-quality telescope lenses.
Frequently asked questions
Is boron essential for human health?
Boron is definitely essential for plant growth and agricultural crop yields. However, its exact status as a vital nutrient for humans remains an active subject of scientific research.
Why does boron form such complex molecules?
Boron has only three outer electrons available for chemical bonding. It relies on sharing electrons across multiple atoms to satisfy its need for a full outer shell.
What is borax and how is it related to boron?
Borax is a naturally occurring mineral compound that contains boron, sodium, oxygen, and water. It is the main source that mining companies use to extract pure boron.
Related terms
Sources & references
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