Boron
Boron (B) is the 5th element on the periodic table and is not particularly abundant in the universe or on Earth, but there is enough of it on Earth to satisfy certain applications in human society. For energy applications boron is used as a dopant in solar panels (and elsewhere in the silicon industry]] and as a neutron poison to turn off nuclear reactors.
Boron has 3 valence electrons, and can be an exception of the octet rule. Boron can be stable with 8 valence electrons as well as with 6 valence electrons, such as in boron trifluoride (BF3).[2] Silicon has four valence electrons, so boron is used in small quantities in solar panels (and other silicon based devices) to make the 'p' side of p-n junction. Nuclear reactors use reservoirs of boric acid to act as a neutron poison to absorb the neutrons that cause fission chain reactions.
Figure 1 shows a Bohr model of the boron atom. Keep in mind that the Bohr model is a simplification, the Quantum Mechanical model is more accurate and better depicts the unique bonding properties of Boron.
Some useful atomic properties of boron include:[3]
| Atomic weight | 10.811 |
| Density | 2.37 g/cm3 |
| Boiling point | 2348 K |
| Melting point | 4273 K |
Uses
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Due to boron's high neutron cross section it is an effective neutron absorber. This makes it useful in the control rods of nuclear reactors to maintain a safe nuclear chain reaction. This also makes it desirable as a radiation shield, as well as a neutron detector.[3]
Several compounds of boron are in common use commercially.
- Boric oxide is used to manufacture tough, heat resistant glass known as Pyrex.[5] Figure 2 shows a borosilicate measuring cup, made up of silica, boron, sodium, and aluminium. Since the glass is very thermally and chemically resistant, it is widely used in scientific laboratories.[6]
- The most important compound of boron is known as sodium borate pentahydrate, used to manufacture fibreglass insulation and bleach.
- Boric acid (H3BO3) is used in insulation as a flame retardant.[3]
Boron also has a characteristic green color when ignited, so it is commonly used in pyrotechnics and flares.
For Further Reading
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- Periodic table of elements
- Atom
- Neutron
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References
- ↑ Wikimedia Commons (2010). (Accessed May 28, 2026). Electron shell 005 Boron [Online]. Available: https://commons.wikimedia.org/wiki/File:Electron_shell_005_Boron.png
- ↑ Goyal, V. (2025). (Accessed May 28, 2026). Boron trifluoride (BF3) lewis dot structure, molecular geometry, polar or nonpolar, hybridization, Bond angle [Online]. Available: https://topblogtenz.com/bf3-lewis-structure-molecular-geometry-polar-or-nonpolar-hybridization-bond-angle/
- ↑ 3.0 3.1 3.2 Jefferson Labs. (Accessed February 6, 2016). The Element Boron [Online], Available: http://education.jlab.org/itselemental/ele005.html
- ↑ Wikimedia Commons (2017). (Accessed May 28, 2026). Pyrex (33207525465) [Online]. Available: https://commons.wikimedia.org/wiki/File:Pyrex_(33207525465).jpg
- ↑ Royal Society of Chemistry. (Accessed February 6, 2016). Boron [Online], Available: http://www.rsc.org/periodic-table/element/5/boron
- ↑ Borosil Scientific (2025). (Accessed May 28, 2026). A Comprehensive Guide to Borosilicate Glass: Understanding Types, Composition, and Properties [Online]. Available: https://www.borosilscientific.com/a-comprehensive-guide-to-borosilicate-glass-understanding-types-composition-and-properties/
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