Figure 1. Boron, atomic weight of 10.811 and atomic number of 5.[1]

Boron (B) is the 5th element on the periodic table. It is not found in high abundance in the universe or on Earth, however there is enough of it on Earth to satisfy its certain applications in human society.

Some useful atomic properties of boron include:[2]

Atomic weight 10.811
Density 2.37 g/cm3
Boiling point 2348 K
Melting point 4273 K


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.[2]

Several compounds of boron are in common use commercially. Boric oxide is used to manufacture tough, heat resistant glass known as Pyrex.[3] 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.[2]

Boron also has a characteristic green color when ignited, so it is commonly used in pyrotechnics and flares.


  1. Made internally by a member of the Energy Education team, information from Jefferson Labs:
  2. 2.0 2.1 2.2 Jefferson Labs. (Accessed February 6, 2016). The Element Boron [Online], Available:
  3. Royal Society of Chemistry. (Accessed February 6, 2016). Boron [Online], Available:

Authors and Editors

Jordan Hanania, Jason Donev
Last updated: February 18, 2016
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