The conversion of red phosphorus to white phosphorus

The formation of yellow fumes from red powder

Scientific name: The conversion from one phosphorus allotropic modification to another


How to make white phosphorus

How to make white phosphorus at home

by Orbital Overlap

Превращение красного фосфора в белый


Wear eye protection goggles. Vapours of white phosphorus are poisonous! Perform the reaction in a hood or outdoors.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

4 P → P4


  1. Red phosphorus

Step-by-step instruction

  1. Place a small amount of red phosphorus into the U-tube.
  2. Heat the red phosphorus using a gas burner. Vapours of white phosphorus must move to the second knee of the tube and condense in the form of an orange solid.
  3. Remove the resulting white phosphorus.
  4. Observe autoignition of white phosphorus.

Scientific background

There are several allotropic modifications of phosphorus. When heated, the structure of the crystal lattice of red phosphorus is changed. Thus, formation of white phosphorus occurs. The orange color of white phosphorus is caused by red phosphorus impurities.

White phosphorus is much more chemically active and pyrophoric.


Published on 30 June 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst