Chemistry » Metals, Metalloids, and Nonmetals » Occurrence, Preparation, and Properties of Phosphorus

# Occurrence, Preparation, and Properties of Phosphorus

## Occurrence, Preparation, and Properties of Phosphorus

The industrial preparation of phosphorus is by heating calcium phosphate, obtained from phosphate rock, with sand and coke:

$${\text{2Ca}}_{3}{({\text{PO}}_{4})}_{2}(s)+{\text{6SiO}}_{2}(s)+\text{10C}(s)\;\stackrel{\phantom{\rule{0.4em}{0ex}}\text{Δ}\phantom{\rule{0.4em}{0ex}}}{\to }\;{\text{6CaSiO}}_{3}(l)+\text{10CO}(g)+{\text{P}}_{4}(g)$$

The phosphorus distills out of the furnace and is condensed into a solid or burned to form P4O10. The preparation of many other phosphorus compounds begins with P4O10. The acids and phosphates are useful as fertilizers and in the chemical industry. Other uses are in the manufacture of special alloys such as ferrophosphorus and phosphor bronze.

Phosphorus is important in making pesticides, matches, and some plastics. Phosphorus is an active nonmetal. In compounds, phosphorus usually occurs in oxidation states of 3−, 3+, and 5+. Phosphorus exhibits oxidation numbers that are unusual for a group 15 element in compounds that contain phosphorus-phosphorus bonds; examples include diphosphorus tetrahydride, H2P-PH2, and tetraphosphorus trisulfide, P4S3, illustrated in the figure below.

P4S3 is a component of the heads of strike-anywhere matches.