Boron Compounds and Applications

Oct 22, 2021 | SCIENCE

Boron is a naturally occurring element found in our environment as the compounds called borates. Boron and its compounds have several applications. From supporting plant and animal health to being an efficient alternative for decarbonization, the applications of boron are wide and varied.
What is Boron

Boron and Borates

The element boron occurs naturally in our environment and is combined with oxygen and other elements as compounds called borates. Boron’s unique properties make it useful in several fields. At the basic level—given its several therapeutic properties—it’s vital for plant and animal life. While having vast applications in agriculture and industries, it’s also leading us forward to a sustainable low carbon economy. 


Boron Compunds

Boron occurs in the form of borates in the oceans, coal, sedimentary rocks, and some soils. It is a semimetal of main Group 13. It is abundant in nature, with concentrations of about 10 mg/kg in the Earth’s crust and about 4.5 mg/liter in the ocean. It is indispensable for plant growth and has wide industrial and agricultural applications. 

The most important commercial borate products and minerals are borax pentahydrate, borax, sodium perborate, boric acid, colemanite, and ulexite. 

Borax pentahydrate

Borax pentahydrate (Na2B4O7·5H2O) is also known as Borax 5 Mol, Sodium Tetraborate, and Borax 5-hydrate. It’s made up of crystalline white granules. In a solution, it is somewhat alkaline. Glass fiber is the most common use for borax pentahydrate in the insulation industry. In ceramics, borax pentahydrate is utilized as a glazing raw ingredient because of its high water solubility. Because of its ability to generate a smooth, sticky, protective, clean, and burr-free liquid at high temperatures, borax pentahydrate is employed as a protective slag-former and fusing accelerator in the non-ferrous metal sector. It is used for killing weeds as well as softening the drinking tap water and has been used for centuries as an ingredient in laundry detergents.


The compound of sodium tetraborate with water (NaBO·xH20) is commonly known as borax or sodium olefin. It can be obtained by acidifying an aqueous solution containing it, which then evolves hydrogen gas due to the interaction between these two materials. Borates are alkaline enough for pH balancing without lowering the base concentration. It is widely used as an agricultural pesticide or herbicide and is found in household products like detergents, bleach, paint, leather, and other cleaning agents. Borax-based ultra-high-strength steel has been discovered to make automobiles lighter and less prone to corrosion, while ceramic frits created with borax aid in making tough glazes on tiles, roofs, silos, appliances, etc. For soldering or welding, it is utilized as flux. 

Sodium perborate

Sodium perborate is a chemical compound that has the formula, NaBO3·nH2O. It’s commonly encountered in anhydrous form and as hexahydrate on crystallization. These salts are white solids with no odor and soluble in water. When sodium perborate monohydrate is produced, it’s a process that takes place in fluidized-bed reactors. This means particles of metaborates and hydrogen peroxide are pulverized at about 100 °C to produce granular nuggets known as “sodium metaborate.” Sodium perforated is the oldest and the most popular bleaching agent. It also has anti-microbial properties. Sodium perborate is used as a preservative in ophthalmic medicines for dry eyes. It has forensic applications. It is widely used in the industry as a disinfectant.  Since 2004, Health Canada has licensed perboric acid in the form of sodium perborate for use as a disinfectant for medical devices.  

Boric acid 

Boric acid (H3BO3) also called hydrogen borate or orthoboric acid is a weak Lewis Acid of boron. Boric acid and borate salts occur naturally in rocks, soil plants, and water. Boric acid is an excellent tool for controlling a wide variety of pests. It can be used to get rid of insects, spiders, and mites; it also controls weeds. It also acts as a fertilizer and wood preservative. It is used on a variety of sites, such as sewage systems. The commercial formulations of boric acid include liquids (solutions), granules, wettable powders, or dust in concentrations ranging from 1% to nearly 100%. Mostly used in industrial processing and manufacturing, Boric acid can also be found in cosmetics, lotions, soaps, mouthwash, toothpaste, astringents, and eyewashes. Products that contain this ingredient have been registered domestically (in America) since 1948. 


Colemanite (Ca2B6O11·5H2O) is hydrated calcium borate, an altered variation of borax. Over 200 minerals contain boron but only colemanite has been commercially important due to its 50% B2O3 content which ultimately makes it useful for the manufacturing industry, oil refining revitalization, detergents, and textiles industry, etc. It is a popular mineral among collectors. It forms at lower pHs and warmer temperatures than other similar compounds like ulexite. Colemanite is found all over the world, especially near granite rocks. 


Ulexite (NaCaB5O6(ΟH)6·5H2O) is a mineral that consists of hydrated sodium and calcium borates. Individual crystals are colorless, but they can form into more common nodular or lenslike aggregates (often resembling cotton balls) to give off a white luster like silk. Ulexites are useful for their fiber-optic properties; this property led it to be called “television rock”. Ulexite fibers function as optical fibers, transporting light along their lengths by internal reflection. A good-quality specimen of ulexite will exhibit an image of whichever surface is next to its opposite side when cut with flat polished sides perpendicular to the direction of the fibers. Ulexite is rare, but it may be derived from boron leached out of sediments and pyroclastic rocks by flowing waters.

It exists in different forms, the most common of which is amorphous boron, a dark powder. At standard temperatures, boron is a poor electrical conductor but is a good conductor at high temperatures. It doesn’t react to oxygen, water, acids, and alkalis but it reacts with metals to form borides. 

How Boron is extracted and prepared 

Boron occurs combined as borax, kernite, and tincalconite (hydrated sodium borates), the major commercial boron minerals, especially concentrated in the arid regions of California, and as widely dispersed minerals such as colemanite, ulexite, and tourmaline. The most important source of boron is rasorite which is located in the Mojave Desert in California. Sassolite—natural boric acid—occurs, especially in Italy. Boron occurs as an orthoboric acid in some volcanic spring waters, and as borates in the minerals borax and colemanite. Major borax deposits can be found in Turkey. 

Pure boron is prepared by reducing boron trichloride or tribromide with hydrogen, on electrically heated filaments. Impure, or amorphous, boron can be prepared by heating the trioxide with magnesium powder.

Boron Extraction - US Borax

Properties of Boron 

Pure crystalline boron is a black, lustrous semiconductor; i.e., it conducts electricity like a metal at high temperatures and is almost an insulator at low temperatures. It is hard enough to scratch some abrasives, such as carborundum, but too brittle for use in tools. It absorbs radiation very well. It constitutes about 0.001 percent by weight of Earth’s crust.

As stated in, pure boron exists in at least four allotropes. Closed cages containing 12 boron atoms arranged in the form of an icosahedron occur in the various crystalline forms of elemental boron. Crystalline boron is almost inert chemically at ordinary temperatures. Boiling hydrochloric acid does not affect it, and hot concentrated nitric acid only slowly converts finely powdered boron to boric acid (H3BO3). Boron exhibits non-metallic characters. 

Applications of boron

Boron serves a variety of purposes in multiple fields:

Health Care

Nothing Boring About Boron“—an article published in the “Integrative Medicine: A Clinician’s Journal”, discusses that the micronutrient boron is crucial in the functioning of the metabolism, thus, rendering it indispensable for the plant, animal, and human health, and as recent research proposes, for the evolution of life on Earth. It helps with bone development and strengthening, wound healing, the production and metabolism of sex steroids and vitamin D, and the absorption and use of calcium and magnesium. Moreover, boron has anti-inflammatory effects which help cope with arthritis and improve brain function. Boron also helps conditions such as diabetes, high cholesterol, and vaginal yeast infections. Boron (neutron capture therapy) has also proven to be a less expensive, less invasive, and better alternative for cancer treatment. 

Boron is a micronutrient that helps to grapple with the crisis of famines and food insecurity by providing much-needed nutritional support to the malnourished. 

Further studies prove that boron deficiency can have serious implications. Weak bones, impaired cognitive functions, low immunity, etc. Thus, making low boron intake a relevant nutritional concern. 


Boron helps to remove carbon dioxide from industrial emissions. We can likewise mix it with coal and different fuels as a method for lessening their carbon density. The utilization of boron not just gives an alternate fuel source for coal power plants. But it also decreases greenhouse gas emissions and assists with combating environmental change by bringing down CO levels. 

Boron helps in keeping the houses warm in winters and cool in summers, thus, saving fuel, energy, and money. Also, borates play a key role in renewable development as they’re the key ingredient in a type of light-emitting diode (LED) that can be powered by solar, wind, or hydropower. Boron also helps in the functioning/building of wind turbines, solar panels, lithium batteries, and nuclear power plants. 


Boron (B) is a micronutrient that is crucial for the growth and health of all crops. It is a mobile nutrient within the soil, meaning it is prone to movement within the soil. It is a component of the plant’s reproductive structures and helps build cell walls. 

Boron deficiency usually leads to empty pollen grains, poor pollen vitality, and a reduced number of flowers per plant. It can cause stunting, rough leaves, and interveinal chlorosis of the leaf blades.

Moreover, boron improves root uptake of phosphorus (P) and potassium (K) by maintaining the proper function and structure of root cell membranes. Thus, boron fertilizers play an important role. Boron is also used in pesticides. In the long run, boron plays an important role in ensuring food security. 

Industrial uses

One major commercial compound of boron is sodium tetraborate decahydrate Na2B4O7 · 10H2O, or borax, used for insulating fiberglass. The textile industry depends heavily on boric acid. Borax is used in sodium perborate bleach.

Compounds of boron are used in organic synthesis, in the manufacture of a particular type of glasses, and as wood preservatives. Given their high strength and lightweight, boron filaments are used for advanced aerospace structures. Boron also works as a fire retardant. 

Be it detergents or preservatives, boron very easily manages to find its way into our households due to its countless daily applications.