Phosphorus Trichloride


Phosphorus trichloride (phosphorus chloride, PCl3) is a colorless fuming liquid that reacts violently with water to liberate phosphoric acid and hydrogen chloride (HCl) gas. PCl3 is a strong oxidizer and will readily react with many organic compounds. The liquid and its byproduct are both highly corrosive to eyes, skin and mucous membranes.

Emergency Procedures

Skin Contact:  Causes severe burns with local pain and redness. Rinse with copious amounts of water for at least 15 minutes. Seek medical attention as needed. Thoroughly clean contaminated clothing and shoes before reuse or discard.

Eye Contact:  Causes severe burns with local pain and blurred vision. Irreversible damage can occur from vapors and liquid contact. Rinse with copious amounts of water for at least 15 minutes. Seek medical attention immediately.

Ingestion:  Abdominal pain, vomiting. Ingestion can be fatal. Do not induce vomiting. Drink 2-3 glasses of water and seek medical attention immediately.

Inhalation: Extremely destructive to tissues of the mucous membranes and upper respiratory tract. Symptoms may include burning sensation, coughing, wheezing, laryngitis, shortness of breath, headache, nausea and vomiting. Move to fresh air and seek medical attention immediately.

Fire:  Use Class D extinguisher, such as Met-L-X or smother the fire with dry sand. Do not use water, carbon dioxide or halogenated extinguishing agents.

Spill:  Control all sources of moisture. Wearing personal protective equipment, cover the spill with sand. Scoop spilled materials with spark-resistant tools and place in a container for disposal. DO NOT USE WATER.


Upon contact with water or heat, PCl3 produces an exothermic reaction involving the release of acid gases. Wear safety glasses, impervious gloves and a fire-retardant laboratory coat. Control ignition sources and avoid contact with water or moisture. Keep a supply of dry sand available in the work area and ensure there is a Class D extinguisher immediately available.

When large quantities of PCl3 will be used, work in dry surroundings, such as in a glove box. Avoid contact with water and humid environments.

PCl3 is incompatible with most organic reagents, hydrated reagents, alkali earth metals, strong oxidizers and caustics, lead dioxide, flourine, and a wide variety of other materials. PCl3 will corrode most transition metals particularly in the presence of moisture.

Do not heat PCl3 without proper containment for generated hydrochloric and phosphoric acid vapors. Reagent may form phosphine and diphosphine gases by thermal decomposition.


Store in tightly sealed containers in a cool dry place, separate from combustible materials. Storage containers may pressurize if contaminated with water.


Store wastes in tightly sealed containers. Dispose as hazardous waste.

For More Information

See SDS for Phosphorus Trichloride.


Stanley Howell
Sr. Program Manager - Chemical Safety

Steve Elwood
Associate Director for Laboratory Safety