Phosphorus is an element that is found in four different pure forms. Each form has different characteristics. Chemically it is a non-metal, related in its properties to the elements nitrogen and astatine.
Phosphorus was first isolated in 1669 by H. Brandt. It is the first element whose date of discovery is known. Brandt isolated phosphorus from animal urine. Phosphorus occurs in compound form in all fertile soils. It is necessary for all plant and animal life. In man it is found mainly in bones, teeth, muscles, and nervous tissues.
The most common form of phosphorus is a yellow waxy solid. This form is originally white, almost colorless, but turns yellow when exposed to light. Yellow phosphorus melts at 111.6 °F, is extremely poisonous, and must be stored and cut underwater to prevent fire. When moist yellow phosphorus is exposed to air, it burns, forms phosphorus pentoxide, and gives off a glow from the heat generated. This glow is a chemical change and is unrelated to phosphorescence. The only similarity between phosphorus and phosphorescence is in the word root phosphor which means "light bearer."
Red phosphorus, another form, is widely used in making safety Matches. Red phosphorus is produced by heating yellow phosphorus or exposing it to a bright light. It is not poisonous and must reach 500 °F to burn. Red phosphorus is used in making bronzes and medicines and in gas analysis.
There are other forms of phosphorus, named for their colors, black, scarlet, and violet. Scarlet phosphorus is produced by dissolving yellow phosphorus in phosphorus tribromide and heating it to 357 °F. The solid scarlet phosphorus then settles out. Violet or metallic phosphorus is produced by heating red phosphorus in contact with lead for ten hours at 932 °F. The phosphorus dissolves in the lead and upon cooling it separates as violet phosphorus.
Phosphorus for commercial purposes is obtained from rock Phosphate, a phosphorus-rich mineral. Rock phosphate is purified by heating with sand and carbon. France and the United States are the largest producers of rock phosphate. Phosphorus is the eleventh most abundant element.
Phosphorus (symbol P) has an atomic number of 15. Its atomic weight is 30.9738 (30.975, O = 16).
