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General | |||||||||||||
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Name, Symbol, Number | Phosphorus, P, 15 | ||||||||||||
Chemical series | Nonmetals | ||||||||||||
Group, Period, Block | 15 (VA), 3 , p | ||||||||||||
Density, Hardness | 1823 kg/m3, __ | ||||||||||||
Appearance | colorless/red/silvery white | ||||||||||||
Atomic Properties | |||||||||||||
Atomic weight | 30.973761 amu | ||||||||||||
Atomic radius (calc.) | 100 (98) pm | ||||||||||||
Covalent radius | 106 pm | ||||||||||||
van der Waals radius | 180 pm | ||||||||||||
Electron configuration | [Ne]3s2 3p3 | ||||||||||||
e- 's per energy level | 2, 8, 5 | ||||||||||||
Oxidation states (Oxide) | ±3, 5, 4 (mildly acidic) | ||||||||||||
Crystal structure | Monoclinic | ||||||||||||
Physical Properties | |||||||||||||
State of matter | Solid | ||||||||||||
Melting point | 317.3 K (111.6 °F) | ||||||||||||
Boiling point | 550 K (531 °F) | ||||||||||||
Molar volume | 17.02 ×10-3 m3/mol | ||||||||||||
Heat of vaporization | 12.129 kJ/mol | ||||||||||||
Heat of fusion | 0.657 kJ/mol | ||||||||||||
Vapor pressure | 20.8 Pa at 294 K | ||||||||||||
Speed of sound | no data | ||||||||||||
Miscellaneous | |||||||||||||
Electronegativity | 2.19 (Pauling scale) | ||||||||||||
Specific heat capacity | 769 J/(kg*K) | ||||||||||||
Electrical conductivity | 1.0 10-9/m ohm | ||||||||||||
Thermal conductivity | 0.235 W/(m*K) | ||||||||||||
1st ionization potential | 1011.8 kJ/mol | ||||||||||||
2nd ionization potential | 1907 kJ/mol | ||||||||||||
3rd ionization potential | 2914.1 kJ/mol | ||||||||||||
4th ionization potential | 4963.6 kJ/mol | ||||||||||||
5th ionization potential | 6273.9 kJ/mol | ||||||||||||
Most Stable Isotopes | |||||||||||||
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SI units & STP are used except where noted. |
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Notable Characteristics Common phosphorus forms a waxy white solid that has a characteristic disagreeable smell but when it is pure it is colorless and transparent. This non metal is not soluble in water, but it is soluble in carbon disulfide. Pure phosphorus ignites spontaneously in air and burns to phosphorus pentoxide.
Early matches used white phosphorus in their composition, which was dangerous due to its toxicity. Murders, suicides and accidental poisonings resulted from its use (An apocryphal tale tells of a woman attempting to murder her husband with white phosphorus in his food, which was detected by the stew giving off luminous steam). In addition, exposure to the vapors gave match workers a necrosis of the bones of the jaw, the infamous "phossy jaw." When red phosphorus was discovered, with its far lower flammability and toxicity, it was adopted as a safer alternative for match manufacture. Occurrence Due to its reactivity to air and many other oxygen containing substances, phosphorus is not found free in nature but it is widely distributed in many different minerals. Phosphate rock, which is partially made of apatite (an impure tri-calcium phosphate mineral) is an important commercial source of this element. Large deposits of apatite are in Russia, Morocco, Florida, Idaho, Tennessee, Utah, and elsewhere.
The white allotrope can be produced using several different methods. In one process, tri-calcium phosphate, which is derived from phosphate rock, is heated in an electric or fuel-fired furnace in the presence of carbon and silica..Elemental phosphorus is then liberated as a vapor and can be collected under phosphoric acid. Precautions This is a particularly poisonous element with 50 mg[?] being the average fatal dose. The allotrope white phosphorus should be kept under water at all times due to its hyper reactivity to air and it should only be manipulated with forceps since contact with skin can cause severe burns. Chronic white phosphorus poisoning of unprotected workers leads to necrosis of the jaw called "phossy-jaw[?]". Phosphate esters are nerve poisons but.inorganic phosphates are relatively nontoxic. Phosphate pollution occurs where fertilizers or detergents have leached into soils.
When the white form is exposed to sunlight or when it is heated in its own vapor to 250 °C, it is transmuted to the red form, which does not phosphoresce in air. The red allotrope does not spontaneously ignite in air and is not as dangerous as the white form. Nevertheless, it should be handled with care because it does revert to white phosphorus in some temperature ranges and it also emits highly toxic fumes that consist of phosphorus oxides when it is heated.
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