Boron: Definition, Occurrence, Properties & Uses

An element belonging to the p-block, is essential for the cell walls of plants. However, Boron is also considered poisonous to animals if taken in higher doses by upsetting the body’s metabolism. In this article, we will study more about this exciting element, Boron, which is useful on the one hand but dangerous on the other hand. Boron is a trace mineral that plays a variety of critical roles in metabolism, making it essential for plant, animal, and human health, as well as, according to a new study, possibly for the evolution of life on Earth.

Boron is a chemical element with atomic number 5 and the symbol B. It is a brittle, dark, glossy metalloid in its crystalline form and a brown powder in its amorphous form. Because it is the lightest element in the boron group, it has three valence electrons for building covalent bonds, resulting in a variety of compounds such as boric acid, sodium borate, and boron carbide, which is an ultra-hard crystal.

In this article, we will learn in detail about Boron: Definition, Occurrence, Properties & Uses, etc. Continue reading to know more.

What is Boron?

Boron is a chemical element with symbol \({\text{B}}\) and atomic number \(5\) and has an average atomic mass of \(10.811\) amu. It was first isolated in \(1808\) by French chemists Joseph-Louis Gay-Lussac and Louis-Jacques Thenard and independently by British chemist Sir Humphry Davy by heating boron oxide \(\left( {{{\rm{B}}_{\rm{2}}}{{\rm{O}}_{\rm{3}}}} \right)\) with potassium metal. The name is derived from the Arabic ‘buraq’, which was the name for borax, the compound from which the boron was first prepared.

Occurrence of Boron

Boron is a naturally occurring element that can be found dispersed in the environment in various forms combined with oxygen and other elements in compounds such as boric acid, borates, and borosilicates. It is a low-abundance element in the Solar System and the Earth’s crust. It constitutes about \(0.001\) per cent by weight of Earth’s crust.

Atomic Structure of Boron

The atomic number of boron is \(5,\) which indicates five electrons revolving around the atom’s nucleus, and it has five protons and six neutrons present in the nucleus. The electronic configuration according to electron distribution in shells is \(2,3,\) indicating that there are three valence electrons, and the valency of the element is \(3.\) Also, according to the sub-shell distribution, the electronic configuration of boron is \({\rm{1}}{{\rm{s}}^{\rm{2}}}{\rm{2}}{{\rm{s}}^{\rm{2}}}{\rm{2}}{{\rm{p}}^{\rm{1}}}\).

Boron in Periodic Table

It is the first element of group \(13\) and is positioned in the second period of the periodic table.

Preparation of Boron

1. Pure boron can be prepared by reducing volatile boron halides with hydrogen at high temperatures.
2. Ultrapure boron is produced by decomposing diborane at high temperatures and then purified through zone melting.

Properties of Boron

Let us go through the different properties of Boron –

Physical Properties

1. Boron exists in two allotropic forms- crystalline and amorphous.
2. It is a lighter element.
3. It is a metalloid.
4. It exhibits a \(+3\) oxidation state.
5. It forms covalent bonds with compounds.
6. It has a high melting and boiling point.
7. It is a poor conductor of electricity.
8. It has a high ionization enthalpy.
9. It burns bright green in flame tests.

Chemical Properties

1. Reaction with Hydrogen- Boron forms hydrides on reacting with hydrogen.
2. Reaction with halogens- Boron reacts vigorously with fluorine, chlorine, and bromine to form boron (III) trihalides.
   \({\rm{2B + 3}}{{\rm{F}}_{\rm{2}}} \to {\rm{2B}}{{\rm{F}}_{\rm{3}}}\)
   \({\rm{2B + 3C}}{{\rm{l}}_{\rm{2}}} \to {\rm{2BC}}{{\rm{l}}_{\rm{3}}}\)
3. Reaction with Oxygen- Boron in its crystalline form is unreactive, but in its amorphous form, it combines with oxygen in the air to form boron trioxide.
   \({\rm{4B + 3}}{{\rm{O}}_{\rm{2}}} \to {\rm{2}}{{\rm{B}}_{\rm{2}}}{{\rm{O}}_{\rm{3}}}\)
4. Formation of hydroxides- Boron does not react with water, but oxides of boron react with water to form hydroxides or boric acid.
   \(\mathrm{B}_{2} \mathrm{O}_{3}+3 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{~B}(\mathrm{OH})_{3}\)
5. Reaction with metals- Boron combines with various metals to form a class of compounds called borides which are harder, chemically less reactive, and electrically less resistive and have a higher melting point than the corresponding pure metallic elements.
6. Boron does not react with acids or alkalis.

Isotopes of Boron

There are a total of \(11\) isotopes of boron which range from \({\rm{B – 7}}\) to \({\rm{B – 17}}\) So naturally, boron occurs as two isotopes which are \({}_5^{10}{\rm{B}}\left( {19.9\% } \right)\) and \({}_5^{11}{\rm{B}}\left( {80.1\% } \right)\)

Attempt Mock Tests

Anomalous Behaviour of Boron

Boron, the first member of the group \(13\) elements, shows anomalous behaviour and differs from its family members. The main reasons for differences are as follows:

(a) exceptionally small atomic and ionic size.
(b) high ionization enthalpy.
(c) absence of d orbitals in its valence shell.

Uses of Boron Compounds

Diborane
(i) It is used as a fuel for supersonic rockets.
(ii) For preparing many other boron hydrides.
(iii) It is used as a reducing agent in organic reactions.

Borax \(\left(\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} \cdot 10 \mathrm{H}_{2} \mathrm{O}\right)\)
(i) In the manufacture of enamels, glazes for earthenwares, tiles, pottery, etc.
(ii) As a flux in soldering.
(iii) In the preparation of antiseptic soaps due to their antiseptic action.

Boric Acid \(\left(\mathrm{H}_{3} \mathrm{BO}_{3}\right)\)
(i) It is used as a preservative for milk and foodstuff
(ii) It is used in making antiseptic lotions.

Uses of Boron

(i) It is used in the steel industry to impart hardness to steel. It has replaced costlier metals like \({\rm{Mo,Cr,W}}\) etc.
(ii) In the glass industry for making borosilicates glass.
(iii) \({\rm{B – 10}}\) isotope is used in making control rods as metal borides in nuclear reactors.
(iv) In making composite materials for aircraft in the form of boron filaments.
(v) Boron carbide is used in making bulletproof vests.
(vi) It is a minor nutrient for plants.

Health Effects of Boron on Humans

Humans can be exposed to boron through fruit and vegetables, water, air and other products.
When humans consume large amounts of boron-containing food, the boron concentrations in their bodies may rise to levels that can cause health problems that can infect the stomach, liver, kidneys and brains and eventually lead to death.

Humans can be exposed to boron through fruit and vegetables, water, air and other products. When humans consume large amounts of boron-containing food, the boron concentrations in their bodies may rise to levels that can cause health problems that can infect the stomach, liver, kidneys and brains and eventually lead to death.

Boron is used for building strong bones, treating osteoarthritis, as an aid for building muscles and increasing testosterone levels, and for improving thinking skills and muscle coordination.

FAQs

We have provided some frequently asked questions about Boron here:

Q1. Is Boron safe to ingest?
Ans: Yes, boron is safe to ingest if it’s taken by mouth and its quantity does not exceed \(20 mg\) daily.

Q2. What are the five physical properties of Boron?
Ans:  Boron exists in two allotropic forms- crystalline and amorphous. It is a metalloid. It exhibits a \(+3\) oxidation state. Boron forms covalent bonds with compounds. It has a high melting and boiling point.

Q4. What are three interesting facts about Boron?
Ans:  Boron is a tough element – very hard and very resistant to heat. Boron is an essential nutrient for all green plants. Boron, in its crystalline form, is very unreactive.

Q3. What are the three uses of Boron?
Ans: In making composite materials for aircraft in the form of boron filaments. Boron carbide is used in making bulletproof vests. It is a minor nutrient for plants.

Q5. Is boron poisonous?
Ans:  At large levels, boron compounds are poisonous to all species studied, although they are not mutagenic or carcinogenic.

In this article, we studied in detail the occurrence and physical and chemical properties of Boron. Also, we explored some of the uses of some important compounds of boron. If you have any questions about this article or general about boron, ping us through the comments section, we will get back to you as soon as possible.