Chemical reactions of the elements
Reaction of phosphorus with air
White phosphorus glows in the dark when exposed to damp air in a process known as chemiluminescence. White phosphorus must be handled with great care. It spontanteously ignites in air at about room temperature to form "phosphorus pentoxide" - actually tetraphosphorus decaoxide, P4O10.
P4(s) + 5O2(g) → P4O10(s)
Under careful control (75% O2, 25% N2, 50°C, 90 mm Hg), a mixture is formed, one of the products within which is "phosphorus trioxide" - actually tetraphosphorus hexaoxide, P4O6.
P4(s) + 3O2(g) → P4O6(s)
Reaction of phosphorus with water
White phosphorus glows in the dark when exposed to damp air in a process known as chemiluminescence.
Reaction of phosphorus with the halogens
White phosphorus, P4, reacts vigorously with all the halogens at room temeperature to form phosphorus trihalides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, Br2, and iodine, I2, to form respectively phosphorus(III) fluoride, PF3, phosphorus(III) chloride, PCl3, phosphorus(III) bromide, PBr3, and phosphorus(III) iodide, PI3.
P4(s) + 6F2(g) → 4PF3(g)
P4(s) + 6Cl2(g) → 4PCl3(l)
P4(s) + 6Br2(g) → 4PBr3(l)
P4(s) + 6I2(g) → 4PI3(g)
White phosphorus, P4, reacts with iodine, I2, in carbon disulphide (CS2) to form phosphorus(II) iodide, P2I4. The same compound is formed in the reaction between red phosphorus and iodine, I2, at 180°C.
P4(s) + 4I2(g) → 2P2I4(g)
Reaction of phosphorus with acids
Phosphorus does not react with dilute non-oxidizing acids.
Reaction of phosphorus with bases