Home More What Is Red Phosphorus? Its properties and uses
What Is Red Phosphorus

What Is Red Phosphorus? Its properties and uses

by Umeeka

Are you wondering what red phosphorus is? People who constantly work in laboratories are very much familiar with this term. But what about the other people? Don’t panic! In my article, I will discuss this element in detail. Here, I have mentioned the structure, properties, sources, and uses of this particular element. Make sure you do check out our FAQ section too. Without wasting any more time, let us get to know more about red phosphorus in depth.

What Is Red Phosphorus?

Red phosphorous is the most commonly used allotropes of phosphorous. This allotrope of phosphorous is considered to be a derivative of the P4 molecule. They usually exist in an amorphous i.e. non-crystalline form.

Let us now check out some more interesting facts about this allotrope of phosphorous.


This allotrope of phosphorus exists in a polymeric chain of tetrahedrally structured P4 molecules. Here, one of the P-P bonds is broken to enable the linking of these tetrahedrons. The structure of this allotrope of phosphorus is illustrated below for you.

ADD Diagram

From the above diagram, we can see that the structure of this allotrope of phosphorus is quite similar to that of a P4 molecule. Every single phosphorus atom in P4 is linked to three other phosphorous atoms in a tetrahedral structure. These tetrahedral structures proceed to bond with neighboring phosphorus atoms when one of these bonds is broken.


Below I have listed down some important properties of this allotrope phosphorus.

Red Phosphorus FormulaP4 (chain)
ColorDeep red color
Atomic Weight30.974 grams per mole
Atomic Number15
Density2.34 grams per cubic centimeter
Melting Point860K
Boiling Point553.7K
Sublimation Point 638.2-863K
Electronic Configuration3s2 3p3

However, this allotrope of phosphorus does not show any phosphorescence (it is a type of photoluminescence).


So, how to make red phosphorus? This allotrope of phosphorus was first discovered by an Austrian chemist. Below I have discussed some important methods through which you can obtain this allotrope phosphorus.

White Phosphorus

  1. For manufacturing this allotrope of phosphorus, you have to heat white phosphorous.
  2. You should heat this white phosphorus at 550K in a steel pot for at least 3-4 days.
  3. Make sure that it is submerged in water while you are heating it.
  4. After 2 days, the temperature is increased up to 672K to distill off any residual white phosphorus.
  5. Now, remove the water from the resulting mixture.
  6. Add sodium carbonate into the mixture.
  7. Let it vacuum dried in order to obtain this allotrope of phosphorus.

Bone Ash Or Phosphorus-Rich Rocks

  1. You can obtain this allotrope of phosphorus from a finely ground powder from phosphorus-rich rocks or animals/fish bones.
  2. This powder or bone is further treated with H2SO4 (sulphuric acid). This results in forming some phosphoric acid with calcium sulfate.
  3. Now, heat this phosphoric acid with charcoal to obtain this allotrope of phosphorus.


Several companies are looking to recover phosphorus from waste materials including urine. In Australia, researchers have produced this allotrope of phosphorus from urine. Sometimes, phosphate rocks may not be available in various regions. In this case, they can approach recycling phosphorus from urine.


Many among us still don’t know what is red phosphorus used for. Let us see some mind-blowing applications of this allotrope of phosphorus.

  • The striking surface of matchboxes is made up of this allotrope of phosphorus and powdered glass. This helps to produce a spark to light a matchstick.
  • Many flares use this allotrope of phosphorus to help in the ignition process.
  • When mixed with magnesium and a binder, this allotrope of phosphorus can be used as a smoke device. It helps to quickly create a smokescreen.
  • A red phosphorus drug such as methamphetamine is produced by this allotrope of phosphorus. Nowadays, it is commonly known as meth. It is made by mixing red phosphorus and iodine to produce hydriodic acid.
  • They can also be used as a flame retardant in many thermoplastics and thermosetting plastics.
  • Even red phosphorus fertilizers are very useful in agriculture.


Is Red Phosphorus Illegal?

Yes, this allotrope of phosphorous is illegal to use. Any person can knowingly or intentionally use them for manufacturing drugs like methamphetamine.

Is Red Phosphorus Dangerous?

Yes, they can be dangerous. It may cause nausea, vomiting, or abdominal pain. Seek medical attention immediately in case you see such symptoms.

What Does Red Phosphorus Do To Your Body?

This allotrope of phosphorus can cause the following health issues to your body.

  • Respiratory tract irritation
  • Bronchitis
  • Liver damage
  • Kidney damage
  • Dermatitis

Can You Buy Red Phosphorus?

Yes, you can buy red phosphorous online as well as offline.


In my above article, I have discussed interesting facts about red phosphorus. They are one of the most concentrated sources of phosphorous. Its atomic structure is made up of four tetrahedrally grouped phosphorous atoms. They are obtained by heating white phosphorus at a very high temperature. You can also find phosphorus naturally from bone or phosphorus-rich rocks. This allotrope of phosphorus is majorly used in the making of methamphetamine. They are also used in producing matches, flares, and various fertilizers. Thus, I covered all the important factors of red phosphorus you should know.

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