Phosphorus

Symbol: P
Atomic number: 15
Category: nonmetals
Group: 15
Period: 3
Block: p
Atomic weight: 30.973762 g/mol
Electrons per shell: 2, 8, 5
CAS number: 7723-14-0
Phase: solid
Density: 1.823 kg/dm³ (white) - near room temperature 2.34 kg/dm³ (red) - near room temperature 2.69 kg/dm³ (black) - near room temperature
Melting point: 317.3 K (44.2 °C, 111.6 °F) (white)
Boiling point: 550 K (277 °C, 531 °F) (white)
Crystal structure: body-centered cubic (white), orthorhombic (black)
Oxidation states: 5, 4, 3, 2, 1, -3
Electronegativity: 2.19 (Pauling scale)
Name's origin: Phosphorus
Name's meaning: in Ancient Greece it was the name of the planet Venus, and is derived from words which translate as 'light carrier'
Facts:
- is commonly found in inorganic phosphate rocks
- due to its high reactivity, phosphorus is never found as a free element in nature on Earth
- is a component of DNA, RNA, ATP, and also the phospholipids which form all cell membranes
- the most important commercial use of phosphorus- based chemicals is the production of fertilizers
- is also widely used in explosives, nerve agents, friction matches, fireworks, pesticides, toothpaste and detergents
- emits a faint glow upon exposure to oxygen
- a wide range of organophosphorus compounds are used for their toxicity to certain organisms as pesticides (herbicides, insecticides, fungicides, etc.) and weaponized as nerve agents
- chronic white phosphorus poisoning leads to necrosis of the jaw bone
- the white phosphorus allotrope should be kept under water at all times as it presents a significant fire hazard due to its extreme reactivity with atmospheric oxygen, and it should only be manipulated with forceps since contact with skin