What is Phosphorus Pentachloride?
Phosphorus pentachloride is a pale greenish-yellow solid with the formula PCl5. Phosphorus pentachloride is known to have the salt-like structure in the crystalline state and to be partly dissociated in solution, especially in polar solvents such as nitrobenzene. It can be prepared by the action of dry chlorine on phosphorus trichloride. As per the law of mass action Phosphorus pentachloride vaporizes almost without dissociation in an atmosphere of chlorine gas or phosphorus trichloride, the dissociation equilibrium is shifted to the left by the presence of product.
Other names – Phosphorus(V) chloride, Pentachlorophosphorane
|Molecular Weight/ Molar Mass||208.24 g/mol|
|Boiling Point||166.8 °C|
|Melting Point||160.5 °C|
Phosphorus Pentachloride Structure – PCl5
Physical Properties of Phosphorus Pentachloride – PCl5
|Appearance||Greenish-yellow crystalline solid|
|Molecular Geometry||Trigonal bipyramid|
|Solubility||Soluble in water|
Chemical Properties of Phosphorus Pentachloride – PCl5
- Phosphorus pentachloride dissolves in water forming phosphoric acid and hydrogen chloride. The chemical reaction is given below.
PCl5 + 4H2O → H3PO4 + 5 HCl
- Phosphorus pentachloride reacts with sulfur dioxide forms Phosphoryl chloride and Thionyl chloride.
SO2 + PCl5 → POCl3 + SOCl2
Uses of Phosphorus Pentachloride – PCl5
- Used as a chlorinating agent and catalyst ш making organic chemicals, intermediates, dyestuffs, etc.
- Used as a catalyst in the manufacture of acetyl cellulose the plastic film on which motion pictures are printed.
- Used as a chlorinating agent in organic chemistry.
- In pharmaceutical industry it is used in the manufacture of penicillin and cephalosporin.
- Used to produce acid chlorides and as a catalyst for cyclisation and condensation reactions.