Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the Greek: phôs (meaning "light") and phoros (meaning "bearer"). A multivalent nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate rocks.
Due to its high reactivity, phosphorus is never found as a free element in nature on Earth. One form of phosphorus (white phosphorus) emits a faint glow upon exposure to oxygen (hence its Greek derivation and the Latin 'light-bearer', meaning the planet Venus as Hesperus or "Morning Star").
Phosphorus is a component of DNA and RNA and an essential element for all living cells. The most important commercial use of phosphorus-based chemicals is the production of fertilizers.
Phosphorus compounds are also widely used in explosives, nerve agents, friction matches, fireworks, pesticides, toothpaste, and detergents.
|Symbol||P||Melting point / °C||α-P4 44.1*|
|Atomic number||15||Boiling point / °C||280.5|
|No. of naturally occurring isotopes||1||Vapour pressure/ mm Hg||0.122(20°C)|
|Atomic weight||30.97376||Dielectric constant (20°C)||4.1(α-P4)|
|Electronic configuration||[Ne]3s23p3||Ionization energy/kJmol-1 I||1012|
|Electrical resistivity (20°C)/μohm cm||1011(α-P4)||Ionization energy/kJmol-1 II||1903|
|Refractive index nD (29.2°C)||1.8244||Ionization energy/kJmol-1 III||2912|
|Density (20°C)/gcm3||1.8232 (α-P4)||*(44.25 when ultrapure)|
|Temperature (oC) @Vap. Pressure||Techniques||Remarks|
|10-8 Torr||10-6 Torr||10-4 Torr||Electron Beam||Crucible||Coil||Boat|
|327||361||402||-||Al2O3||-||-|| Metal reacts violently in air.|
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