Phosphorus

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Phosphorus was discovered accidentally, in 1669, by the alchemist Hennig Brand, in his search for the mythical "Philosopher's Stone". This produced a mysterious glowing substance, which he called phosphorus, meaning "light-destroyer". Phosphorus is the first element to have an assigned discoverer. It is never pure in nature, and is found in different minerals. It has several solid and flammable forms, including red, white, black, and violet phosphorus. The glow seen by Brand was caused by white phosphorus reacting with oxygen. Phosphorus is found mainly in phosphate minerals, such as apatite, its main mineral. Phosphate ions, PO43-, are present in fine china and are an important ingredient in fertilizers. Organic phosphorus compounds (organophosphates) are still used as pesticides and are poisonous.

Summary of properties (P)

Atomic weight30.973761998(5)
Discoverer (year)Brandt, Hennig (1669)
Natural formnon-metal solid (simple cubic)
Electron configuration[Ne] 3s2 3p3
Melting point (ºC)44
Boiling point (ºC)280
Abundance in earth's crust (ppm)1050
Isotope (abundance)31P (100))
Density g/cm31.82
Van der Waals radius (pm)180
Covalent radius (pm)109
Electronegativity (Pauling)2.19
Vaporization enthalpy (kJ/mol)12.40
Enthalpy of fusion (kJ/mol)0.66
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.77
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.002
Oxidation state+5, +3, -3
Electron affinity (eV)0.75
1st Ionization potential (eV)10.4867

Back to the Periodic Table of the Elements.