Have you ever played with matches, drunk a can of soda, or painted a house? If so, then you have witnessed phosphorus in action.
Phosphorus is element fifteen on the periodic table of elements and has an atomic mass of 31. It has five valence electrons and seeks to combine with other elements or compounds to become more stable. Therefore, phosphorus is only found in nature as a component of compounds.
While most commercial phosphorus today is extracted from phosphate ores, it was first isolated from urine in 1669 by Hennig Brand in Germany. He had discovered white phosphorus. This translucent allotrope of phosphorus glows bright green, prompting Brand to name this new element after the Greek word “phosphoros,” meaning “bringer of light.”
White phosphorus consists of four phosphorus atoms bonded in a tetrahedron. It has a bond angle of 60°, causing great strain that can only be reduced by reaction with another substance. White phosphorus is toxic and spontaneously combusts in air. In fact, 0.1 grams of pure white phosphorus is enough to kill a human. This has made it a useful component in rat poison, napalm bombs, and incendiary bombs. White phosphorus had at one time been used as a fire-starter in matches, but, due to its connection with “phossy-jaw” (death of the soft tissue in the lower jaw), another phosphorus allotrope had to be used.
Red phosphorus is a more stable, non-toxic allotrope of phosphorus. It is produced by heating white phosphorus in the absence of air. This allotrope of phosphorus only reacts with substances in the presence of heat. Safety matches use the heat of friction to cause red phosphorus and oxygen react and produce fire. Red phosphorus is also used in smoke screens, tracer bullets, and skywriting.
Compounds containing phosphorus are very useful to us. These phosphates can be found in detergents, fertilizers, fine china, and even our bodies.
Reacting calcium phosphate (a common phosphate rock) and sulfuric acid yields phosphoric acid. Phosphoric acid is used in small amounts to add a tart flavor to soft drinks. This phosphate has also proven useful as a rust inhibitor. Phosphoric acid can be reacted with bases containing sodium to produce sodium triphosphate, a component of some laundry powders and detergents.
Unfortunately, phosphate-containing detergents that reach large bodies of water harm the ecosystem. They serve as nutrients for algae and cause them to grow excessively and take in large amounts of oxygen, making life difficult for other aquatic organisms. To fight this problem, most detergents have removed phosphates from their formulae.
Phosphates are used in some tooth pastes, baking powder, certain shampoos, and pesticides. They are also used to fill small cracks in materials, to soften water, and to make certain types of paint more viscous and flame-retardant. On top of all of this, phosphorus is vital to our existence.
Phosphates can be found in our bones, nervous tissue, and deoxyribonucleic acid. In fact, the average person contains 11 grams of phosphorus per kilogram of mass. Our bodies need phosphorus in order to transfer energy between cells.
The next time you brush your teeth, examine fine china, or watch an airplane create a message in the sky, stop for a moment and think, “There’s phosphorus in that!”
