Phosphorus was discovered by a German, Hennig Brand, in 1669. Brand distilled and reduced 65 gallons of human urine to obtain a few hundred grams of a spongy red substance. He was fascinated by its stange luminescent glow and thought that a young woman who lived a few miles away would be intrigued by his new discovery. So, he put the lump of phosphorus in his pocket set out to walk to his lady-friend's house. Enroute, his clothes spontaneously burst into flames; luckily, the young scientist was able to extinguish the fire by jumping into a nearby river. A slightly less amusing description of the discovery of phosphorus is given by English painter Joseph Wright in his painting 'The Discovery of Phosphorus.'

Symbol: P
Atomic Number: 15
Boiling Point: 553 K
Melting Point: 317.3 K
Density at 300K: 1.82 g/cm3
Covalent radius: 1.06
Atomic radius: 1.23
Atomic volume: 17.0 cm3/mol
First ionization potental: 10.486 V
Specific heat capacity: 0.769 Jg-1K-1
Thermal conductivity: 0.235 Wm-1K-1
Electrical conductivity: 10x10-16106Ω-1m-1
Heat of fusion: 0.63 kJ/mol
Heat of vaporization: 12.4 kJ/mol
Electronegativity: 2.19 (Pauling's)

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(From the Latin Phosphorus, the morning star Venus) A paramagnetic nonmetallic chemical element, normally a white, phophorescent, waxy solid, becoming yellow when exposed to light. It is poisonous and unites easily with oxygen, so it ignites spontaneously at room temperature. When heated in sealed tubes it is converted into a red form, which is nonpoisonous and less flammable than the white. When heated under a pressure of 10,000 atmospheres it is converted into a black powder.

Symbol: P
Atomic number: 15
Atomic weight: 30.973761
Density (at room temperature and pressure): 1.82 g/cc (white)
Melting point: 44.15°C
Boiling point: 280°C
Valence: -3, +3, +5
Ground state electron configuration: [Ne]3s23p3

See also: phosphorus-32


The name sometimes given to the morning star which is also called Heosphorus. Translated into Latin the name becomes Lucifer. It is often personified in poetry as the star which announces the approach of Aurora, the dawn, and which is the bearer of the light of Day.


Table of Sources:
- Ovid, Met. 4,628; Her. 17,112;
- Hyg. Fab 65; 161.

Phos"phor*us (?), n.; pl. Phosphori (#). [L., the morning star, Gr. , lit., light bringer; light + to bring.]


The morning star; Phosphor.

2. Chem.

A poisonous nonmetallic element of the nitrogen group, obtained as a white, or yellowish, translucent waxy substance, having a characteristic disagreeable smell. It is very active chemically, must be preserved under water, and unites with oxygen even at ordinary temperatures, giving a faint glow, -- whence its name. It always occurs compined, usually in phosphates, as in the mineral apatite, in bones, etc. It is used in the composition on the tips of friction matches, and for many other purposes. The molecule contains four atoms. Symbol P. Atomic weight 31.0.

3. Chem.

Hence, any substance which shines in the dark like phosphorus, as certain phosphorescent bodies.

Bologna phosphorus Chem., sulphide of barium, which shines in the dark after exposure to light; -- so called because this property was discovered by a resident of Bologna. The term is sometimes applied to other compounds having similar properties. -- Metallic phosphorus Chem., an allotropic modification of phosphorus, obtained as a gray metallic crystalline substance, having very inert chemical properties. It is obtained by heating ordinary phosphorus in a closed vessel at a high temperature. -- Phosphorus disease Med., a disease common among workers in phosphorus, giving rise to necrosis of the jawbone, and other symptoms. -- Red, or Amorphous, phosphorus Chem., an allotropic modification of phosphorus, obtained as a dark red powder by heating ordinary phosphorus in closed vessels. It is not poisonous, is not phosphorescent, and is only moderately active chemically. It is valuable as a chemical reagent, and is used in the composition of the friction surface on which safety matches are ignited. -- Solar phosphori Chem., phosphorescent substances which shine in the dark after exposure to the sunlight or other intense light.


© Webster 1913.

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