What is Phosphorus
Phosphorus (pronunciation: FOS-fer-es) is a highly-reactive element classified as a non-metal represented by the chemical symbol P [1, 2, 3]. It mainly exists in its two allotropic forms, including the waxy, white solid and the non-crystalline, solid red that is obtained by heating white phosphorus [3, 4, 5].
There are 24 isotopes of phosphorus, ranging from 24P to 47P out of which 31P is stable . While most of the radioactive isotopes are short-lived with half-life periods less than 2.5 minutes, 33P and 32P are the longest-lived with half-lives of 25.34 days and 14.263 days respectively . The least stable among the 24 isotopes of 15P is 25P characterized by a half-life period less than 30 nanoseconds .
Where is Phosphorus Found
Phosphorus does not occur freely in nature, but it forms compounds with other elements in minerals . It is mainly obtained from phosphate rock, including the apatite phosphate mineral .
White phosphorus is commercially produced by treating phosphate rock with silica and carbon in a fuel-fired or electric furnace . Phosphorus is produced as a vapor, which is collected under water . Red phosphorus is manufactured by heating the white form to 250 °C in an inert atmosphere .
The top 3 phosphorus producing countries are China, Mexico, and Morocco while the top 3 phosphorus reserve holders include Morocco, China, and the USA .
Origin of its Name: It is derived from ‘phosphoros’, Greek for the bringer of light 
Who discovered it: The element was discovered by the German merchant and alchemist Hennig Brand [1, 2].
When and How was it Discovered
In 1669, Hennig Brand discovered phosphorus at Hamburg by boiling urine and then heating the residue, which produced phosphorus vapor . Then, he distilled the phosphorus vapor and collected it after condensing it in the water . Hennig Brand decided to keep his discovery secret because he thought that he had produced the Philosopher’s Stone which could be used for turning metals into gold .
Since Hennig needed money, he sold it to Daniel Kraft who displayed it around Europe, capturing the attention of Robert Boyle . He studied phosphorus systematically and found out its characteristics .
|Atomic number||15 |
|CAS number||7723-14-0 |
|Position in the periodic table||Group||Period||Block|
|15 ||3 ||p |
Properties and Characteristics of Phosphorus
|Relative atomic mass||30.974 |
|Atomic mass||30.974 amu |
|Molar mass||30.9737620 ± 0.0000020 g/mol |
|Molecular weight||30.974 g/mol |
|Allotropes||White (yellow), Red, Black |
|Color||Usually, white or pale yellow |
|Melting point/freezing point||44.15 °C, 111.47 °F |
|Boiling point||280.5 °C, 536.9 °F |
|Density||1.823 g cm-3 (white) |
|State of matter at room temperature (solid/liquid/gas)||Solid [1, 5]|
|Electrical Conductivity||1 X 107 S/m |
|Thermal (heat) conductivity||0.236 W/(m K) |
|Specific heat||769 J kg-1 K-1 |
|Bulk modulus||10.9 GPa (red), 4.9 GPa (white) |
|Shear modulus||Unknown |
|Young’s modulus||Unknown |
|– Temperature (K)||400||600||800||1000||1200||1400||1600||1800||2000||2200||2400|
|– Pressure (Pa)||–||–||–||–||–||–||–||–||–||–||–|
|Oxidation states||5, 3, -3 |
|Isotopes||Isotope||Mass||Abundance (%)||Half-life||Mode of decay|
Atomic Data of Phosphorus (Element 15)
|Valence electrons||5 |
|– n||3 |
|– ℓ||1 |
|– mℓ||1 |
|– ms||+1/2 |
|Electron configuration (noble gas configuration)||[Ne] 3s23p3 |
|– Number of electrons||15 |
|– Number of neutrons||16 |
|– Number of protons||15 |
|Radius of Atom|
|– Atomic radius||1.80 Å |
|– Covalent radius||1.09 Å |
|Electronegativity (Pauling-scale)||2.19 |
|Electron affinity||72.037 |
|Ionization energy (kJ mol-1)||1st||2nd||3rd||4th||5th||6th||7th||8th|
What is Phosphorus Used for
- Its allotropic white form is used in incendiary bombs and flares .
- Red phosphorus is used in manufacturing safety matches and is stuck on the matchboxes so that the matches can be lit by striking against them [1, 5].
- Phosphorus compounds are generally used in fertilizers [1, 5].
- Phosphate ores are an important source of ammonium phosphate . The ores are converted into phosphoric acids and then into ammonium phosphate .
- It is also an essential ingredient in the manufacture of steel, phosphor bronze, and some detergents [1, 5]. However, its use in detergents has now been phased out in several countries because it can accumulate in natural water supplies and induce the growth of unwanted algae .
- It is used in manufacturing fine chinaware and special glasses .
- Phosphorus is one of the materials used for producing LEDs (light-emitting diodes) .
Toxicity and Health Effects
An excess of phosphate in the human body can cause soft tissue, hardening of organs, or diarrhea . It can also affect your body’s mechanism of utilizing other essential minerals like zinc, calcium, magnesium, and iron .
While too much phosphorus is toxic for your health, too little of it can weaken your teeth and bones, as well as cause anxiety, fatigue, and loss of appetite .
It is an essential nutrient for plants, which help in moving it through the biosphere, lithosphere, and hydrosphere and this cycle is known as the phosphorus cycle .
- The average amount of phosphates in the human body, mostly in the teeth and bones, is estimated at 750 g (26.5 ounces) .
- A 2013 study has shown that the phosphorus in the Earth’s crust may have been brought by meteorites .
- High phosphorus levels in the blood is a warning sign for heart diseases .
- Since white phosphorus exists as molecules consisting of four atoms arranged in a tetrahedral structure, its graphical representation indicates this tetrahedral shape with a ball-and-stick model .
Cost of Phosphorus
The price of pure phosphorus is $0.3 per gram .