Boron (B) Element: Occurrence, Properties, Uses, Toxicity

Boron, a chemical element with the symbol B is semimetal of main Group 13 (IIIa, or boron group) of the periodic table with the atomic number 5. It exists in numerous forms, the most common of which is amorphous boron, a black powder that is unreactive to oxygen, water, acids, and alkalis. It interacts with metals to generate borides.

Boron (B) Element
Boron (B) Element

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History of Boron

Boron was named after the mineral from which it was extracted, by comparison with carbon, which boron chemically resembled.

Boron was discovered in 1808 by French scientists Joseph-Louis Gay-Lussac and Louis-Jaques Thénard, and separately by English chemist Sir Humphry Davy.

The element was extracted by mixing boric acid (H3BO3) with potassium. Boron is now created by heating borax (Na2B4O7.10H2O) with carbon, however different techniques are employed for high-purity boron.

Occurence of Boron

It is a rare element in the Earth’s crust. It makes up roughly 0.001% of the Earth’s crust by weight.

  • Boron occurs in combination as the principal commercial boron minerals, borax, kernite, and tincalconite (hydrated sodium borates), which are particularly abundant in the dry parts of California, and as widely disseminated minerals such as colemanite, ulexite, and tourmaline.
  • Sassolite, or natural boric acid, is found mostly in Italy.  Almost a hundred borate minerals have been discovered.
  • Boron can be found as an orthoboric acid in some volcanic spring fluids and as borates in minerals such as borax and colemanite. 

The world’s major boron producers are Turkey and the United States. Turkey possesses over 63% of the world’s boron potential and reserves.
Economically significant sources include the ore rasorite (kernite) and tincal (borax ore), both of which are found in California’s Mojave Desert, with borax being the most important source. The biggest deposits of borax may be found in Central and Western Turkey, particularly in the provinces of Eskişehir, Kütahya, and Balkesir.

Isotopes of Boron

Boron has two stable isotopes that occur naturally: 11B (80.1%) and 10B (19.9%).

In natural waters, the mass difference leads in a wide range of δ11B values ranging from -16 to +59. Boron has 13 known isotopes, the shortest-lived of which is 7B, which decays via proton emission and alpha disintegrate.
The boron isotopic ratio has distinct ranges that can be used to identify various earth system components and environmental factors.

Elemental Properties

Electronic Configuration[He] 2s2 2p1
Atomic Number5
Atomic Weight10.81 g.mol -1
Group, Period, and Block13, 2, p-block
Ionic radius0.027 pm
Van der Waals radius0.098 pm
Electronegativity2.04 (Pauling Scale)
2.051 (Allen Scale)
Physical StateSolid
Electron per shells2, 3

Physical Properties of Boron

  • Boron is an amorphous black powder.
  • Boron atoms may bind in a variety of distinct crystal networks known as allotropes.
  • Crystalline boron is a black metal that is exceptionally hard. The chemical compound boron nitride, an allotrope of carbon, is the second hardest solid after diamond.
  • Boron’s melting and boiling points are 2365 K and 4275 K, respectively.
  • Boron has an atomic mass of 10.811 u and an electronic structure of 1s2 2s2 2p1.
  • It has an electronegativity of 2.04 and an ionization potential of -8.298 eV.
  • It has a low density of 2.37 g/cubic cm.
  • The rate of boron oxidation is affected by particle size, crystallinity, temperature, and purity. 
  • Boron has two naturally occurring and stable isotopes, 11B (80.1%) and 10B (19.9%).
  • Boron exhibits intriguing optical characteristics.
  • Ulexite, a boron mineral, has natural fiber optic characteristics.
  • Parts of infrared light are transmitted by the element boron.
  • It is a weak electrical conductor at ambient temperature, but an excellent conductor at high temperatures.
  • Boron has the ability to construct stable covalently linked molecular networks.
  • Boron filaments offer a high strength-to-weight ratio.
  • Elements of boron have a greater energy band gap than silicon or germanium, ranging from 1.50 to 1.56 eV.
Boron(B)Physical Properties
Melting Point2077°C, 3771°F, 2350 K 
Boiling Point4000°C, 7232°F, 4273 K 
Energy of first ionisation800.5 kJ.mol -1
Energy of second ionisation2426.5 kJ.mol -1
Thermal expansionβ form: 5–7 µm/(m⋅K) (at 25 °C)
Thermal conductivity27.4 W/(m⋅K)
Electrical resistivity~106 Ω⋅m (at 20 °C)

Chemical Properties of Boron

  • Amorphous boron is a reactive element whereas in its crystalline state it is extremely inert.
  • Boron preferentially forms covalent bonds rather than ionic bonds.
  • Boron in crystalline form is resistant to damage by boiling hydrofluoric or hydrochloric acid. 
  • It is a weak electrical conductor at ambient temperature, but an excellent conductor at high temperatures.
  • Boron is not reactive when exposed to acids and alkalis at room temperature.
  • Borides are formed when it interacts with metals.
  • When it is halogenated, trihalides are generated as a byproduct. The bromine reaction is shown below.

2B + 3Br2 → 2BBr3

Boron- Uses and Benefits

  • Boron is used to generating a green color in pyrotechnics and flares.
  • Boron has also been employed as an ignition source in some rockets.
  • Boron-10, one of the naturally occurring isotopes of boron, is an excellent neutron absorber and is used in nuclear reactor control rods, as a radiation shield, and as a neutron detector.
  • Boron filaments are employed in the aerospace sector due to their high strength and lightweight characteristics.
  • These compounds are being studied for their potential use in the treatment of arthritis.
  • Sodium octaborate is a flame retardant.
  • Boron compounds are utilized in the manufacture of borosilicate glass.
  • Boron nitride is highly hard, electrically insulating while conducting heat, and possesses lubricating qualities akin to graphite.

Read Also: Helium Element

Health and Environmental Effects of Boron

Health Effects

  • Boron may enter the body through fruits and vegetables, water, air, and consumer items.
  • We have a daily intake of roughly 2 mg and a total of about 18 mg in our bodies.
  • When humans ingest excessive amounts of boron-containing food, the boron concentrations in their systems can reach dangerous levels.
  • Boron can cause mortality by infecting the stomach, liver, kidneys, and brain. When exposed to low levels of boron, discomfort of the nose, throat, or eyes may develop.
  • It takes 5 g of boric acid to make a person sick, and 20 grams or more to endanger their life.
  • Boron poisoning can also result in headaches, chills, restlessness, fatigue, renal damage, dermatitis, alopecia, anorexia, and indigestion.
  • High boron intakes in babies have been linked to anemia, convulsions, erythema, and sparse hair.

Environmental Effects

  • Boron is a naturally occurring element in the environment as a result of weathering and its release into the air, soil, and water.
  • It may also be present in trace concentrations in groundwater. Boron is added by humans through the production of glass, the combustion of coal, the melting of copper, and the application of agricultural fertilizers. Boron concentrations added by people are lower than those naturally added by weathering.
  • Boron exposure by air and drinking water is unlikely, although there is a danger of occupational exposure to borate dust.
  • Boron exposure can also come through consumer items such as cosmetics and laundry detergent.
  • Boron is absorbed from the ground by plants and can enter food chains via plant-consuming animals.
  • Boron has been discovered in animal tissue, however it seems unlikely that it would accumulate.
  • When no impact concentrations are compared to general ambient environmental values, the danger of B to aquatic ecosystems is modest. Natural levels will be higher in a few B-rich places; yet, there is some evidence that organisms may be adapted to the local environment.
  • B is an important element for higher plants, with amounts necessary for optimal development varying between species.
  • In general, the concentration range between deficiency and toxicity is narrow; nevertheless, toxicity due to excess B is significantly less prevalent in the environment than B insufficiency. Levels of B in aquatic plants growing in locations receiving B-rich runoff from irrigated fields are greater than dietary quantities that elicit impacts on young bird growth in the laboratory; however, the bioavailability of such plant-accumulated B in the field is unknown.

Toxicity, Safety, and Precautions

Boron is not classified under the Hazardous Products Regulations (SOR/2015-17). Always be careful when handling or working with chemicals even though they are not listed as hazardous.

Product Safety Department

  • Rinse thoroughly with warm water, including behind the eyelids, for at least 15 minutes if it gets contact with the eyes. Get medical help.
  • If comes to Skin Contact Immediately wash off with lots of water for at least 15 minutes. If symptoms appear, get medical assistance right once.
  • If you inhale the crystalline boron powder, get some fresh air. If symptoms appear, get medical assistance right once.
  • If ingested gargle your mouth with water, drink lots of water. Get medical help if symptoms appear. 

Ensure adequate ventilation. Use personal protective equipment as required. Avoid dust formation.

Safety and Handling

  • Class D extinguishers. Do not use water or foam to extinguish fire.
  • Keep product and empty container away from heat and sources of ignition.
  • Wear personal protective equipment and face shields. Make sure you have enough ventilation. Avoid coming into touch with your skin, eyes, or clothes. Ingestion and inhalation should be avoided. Prevent the production of dust.
  • Use protective eyewear or chemical safety goggles as needed.
  • To avoid skin exposure, wear suitable protective gloves and clothes.
  • Before using gloves, inspect them. Follow the directions for permeability and breakthrough time supplied by the glove provider. Use gloves with caution to avoid skin infection.

Best Boron Supplements

Boron cannot be produced by your body. It’s more of a building block than a finished tool. Instead of producing boron, you should consume it.

Presently, science does not consider it “vital,” because investigations have revealed that boron shortages do not create substantial difficulties. Yet, include boron in your diet appears to offer advantages.

Boron has been demonstrated to benefit numerous physiological processes, including

  • Bone growth and maintenance.
  • Wound Repair.
  • Extracellular matrix protein expression.
  • Sex Hormone Control.
  • Vitamin D deficiency prevention.

Boron Food Supplements

  • Prune Juice
  • Avogado
  • Raisins
  • Peach
  • Grape Juice
  • Apples
  • Pear
  • Peanut Butter
  • Beans

Fun Facts of Boron

  • Boron is derived from the Arabic word “buraq” and the Persian word “Burah,” both of which signify borax.
  • Boron is scarce in its pure form, accounting for less than 0.001% of the earth’s crust. Boron is found in oxygen compounds in nature.
  • The United States government had a program in the 1950s to produce boron hydrides as rocket fuels based on the projected energy release for burning in O2 to generate (HO)3B and H2O. Sadly, substantially less energy is released, which might be due to the fact that the real product is HOBO at flame temperatures. For many years, it was thought that organoboron compounds may be transported into the brain for neutron beam treatment of brain cancers by utilizing 10B’s high neutron absorption cross section.
  • Pure boron is hard and abrasive, but it is also fragile. This metalloid is rare to be found in strong tools; nonetheless, boron-containing ceramics are widely utilized to manufacture cutting tools for machining hard metals.
  • Borosilicate glass is far superior to ordinary glass in quality and durability. Because of its tolerance to temperature fluctuations and most chemicals, it is perfect for scientific glassware.
  • Crystalline boron is uncommon, costly, and highly attractive.
  • Boron might have played a role in the genesis of life on Earth. According to the RNA World Theory, DNA evolved into the genetic material while RNA appeared initially as an unstable molecule. Borates are considered to stabilize ribose, which is one of the building blocks of RNA, suggesting that they were important in the development of RNA and hence life on Earth.


  • Alaa S. Abd-El-Aziz, Macromolecules Containing Metal and Metal-Like Elements Volume 8 Boron-Containing Polymers., (2007) p2. Wiley-Interscience
  • John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
  • John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.

About Author

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Jyoti Bashyal

Jyoti Bashyal, a graduate of the Central Department of Chemistry, is an avid explorer of the molecular realm. Fueled by her fascination with chemical reactions and natural compounds, she navigates her field's complexities with precision and passion. Outside the lab, Jyoti is dedicated to making science accessible to all. She aspires to deepen audiences' understanding of the wonders of various scientific subjects and their impact on the world by sharing them with a wide range of readers through her writing.

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