Chlorine reacting with white phosphorus

Bright burning and the formation of thick smoke

Scientific name: Oxidation of phosphorus in the presence of chlorine


Chlorine reacting with phosphorus (white)

by ChemPics


Wear eye protection goggles. Use gloves. Chlorine is a poisonous gas! 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

P4 + 10 Cl2 → 4 PCl5

Step-by-step instruction

WARNING! This experiment is dangerous! You should NOT perform this at home. ONLY carry out this experiment, if you are a trained chemist, and you understand local safety and legal requirements, which are required to perform such experiments

  1. Fill a 1L-flask with chlorine.
  2. Insert 1 g of white phosphorus into the flask.
  3. Observe the intense burning.

Scientific background

As a halogen chlorine is a strong oxidant. This property of chlorine is due to its position in the periodic table, high electronegativity, the lack of a single electron to fill the outer electron level and the low energy of Cl-Cl bonds. Phosphorus is a nonmetal that has reducing properties. It, especially white phosphorus, has a very high reactivity. Phosphorus is oxidized to phosphorus chloride, which forms the smoke. A large amount of heat is released which provides the ignition.


Published on 30 June 2015

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