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Phosphorus General

Name:Phosphorus Symbol:P
Type:Non-Metal, Nitrogen group Atomic weight:30.97376
Density @ 293 K:1.82 g/cm3 Atomic volume:17.0 cm3/mol

Hennig Brand discovered phosphorus in 1669, preparing it from urine, which naturally contains considerable quantities of dissolved phosphates. The name comes from the Greek word 'phosphoros', meaning bringer of light.

Phosphorus States

State (s, l, g):solid
Melting point:317.3 K (44.2 °C) Boiling point:553.7 K (280.5 °C)

Phosphorus Energies

Specific heat capacity:0.77 J g-1 K-1 Heat of atomization:315 kJ mol-1
Heat of fusion: 0.657 kJ mol-1 Heat of vaporization :12.129 kJ mol-1
1st ionization energy:1011.7 kJ mol-1 2nd ionization energy:1903.2 kJ mol-1
3rd ionization energy:2911.9 kJ mol-1 Electron affinity:72.07 kJ mol-1

Phosphorus Oxidation & Electrons

Shells:2,8,5 Electron configuration: [Ne] 3s2 3p3
Minimum oxidation number:-3 Maximum oxidation number:5
Min. common oxidation no.:-3 Max. common oxidation no.:5
Electronegativity (Pauling Scale):2.19 Polarizability volume:3.6 Å3

Phosphorus Appearance & Characteristics

Structure:special P4 tetrahedral arrangement (white phosphorus) Color:pale yellow
Hardness:0.5 mohs
Harmful effects:

White phosphorus is highly toxic. Skin contact can result in severe burns.


White phosphorus is a highly reactive, waxy, white-yellow, transparent solid with acrid fumes. It emits a weak green glow (luminescence) in the presence of oxygen. It is insoluble in water, but soluble in carbon disulfide. White phosphorus ignites spontaneously in air, burning to the pentoxide (P4O10).

Phosphorus exists in two other main allotropic forms: red, and black (or violet).

Red phosphorus results when white phosphorus is heated or exposed to sunlight.

Black phosphorus is the least reactive allotrope and has a graphite-like structure.


Phosphorus is a vital plant nutrient and its main use - via phospate compounds - is in the production of fertilizers. Just as there are biological carbon and nitrogen cycles, there is also a phosphorus cycle.

Phosphorus is used in the manufacture of safety matches (red phosphorus), pyrotechnics and incendiary shells.

Phosphorus is also used in steel manufacture and in the production of phosphor bronze.

Phosphates are ingredients of some detergents.

Phosphorus Reactions

Reaction with air:vigorous, ⇒ P4O20 ignites Reaction with 6 M HCl:none
Reaction with 15 M HNO3:mild, ⇒ NOx, Reaction with 6 M NaOH:mild, ⇒ PH3 (phosphine) may ignite

Phosphorus Compounds

Oxide(s):P4O10, P4O6 Chloride(s):PCl3, PCl5, P2Cl4
Hydride(s):PH3, P2H4 + more

Phosphorus Radius

Atomic radius:100 pm Ionic radius (1+ ion): pm
Ionic radius (2+ ion): pm Ionic radius (3+ ion):58 pm
Ionic radius (2- ion): pm Ionic radius (1- ion): pm

Phosphorus Conductivity

Thermal conductivity:0.24 W m-1 K-1 Electrical conductivity:1.0 x 10-11 S cm-1

Phosphorus Abundance & Isotopes

Abundance earth's crust:1,050 parts per million by weight, 730 parts per million by moles
Abundance solar system:7 parts per million by weight, 300 parts per billion by moles
Cost, pure:$30 per 100g
Cost, bulk:$ per 100g

Phosphorus does not occur as a free element in nature, but it is found in many different minerals. It is produced commercially from calcium phosphate (phosphate rock). Calcium phosphate is heated in a furnace with silica and carbon to produce vaporized tetraphosphorus, which is then condensed into phosphorus as a white powder under water to prevent oxidation.


Phosphorus has 18 isotopes whose half-lives are known, with mass numbers 26 to 43. Of these only one is stable 31P.

Phosphorus Other



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