Phosphorus Trichloride is an inorganic compound that is usually a colourless liquid or slightly yellow liquid. It is an industrially important compound used in manufacturing several organophosphorus compounds.
Structure and Formula
The chemical formula of Phosphorus Trichloride is PCl3 and its structure is represented below.
In the structure of PCl3, three sp3 hybrid orbitals of P overlap with p-orbitals of Cl to form three P-Cl sigma bonds while the fourth sp3 hybrid orbital contains lone pair of electrons. Thus, PCl3 has a pyramidal structure.
|Odour||Pungent and irritating odour|
|Appearance||Yellow fuming liquid (Colorless in pure form)|
|Solubility||Hydrolyzes in water, soluble in benzene, ether, chloroform, CS2, CCl4, ethanol|
Phosphorus trichloride on further chlorination gives phosphorus pentachloride.
PCl3 + Cl2 → PCl5
In water, the compound dissolves to form phosphoric acid and hydrogen chloride.
PCl3 + 3H2O → H3PO3 + 3HCl
Following are a few ways to prepare PCl3:
- PCl3 is also be obtained when thionyl chloride reacts with white phosphorus.
P4 + 8SOCl2 → 4PCl3 +4SO2 + S2Cl2
- The inorganic compound is prepared by passing dry chlorine gas over heated white phosphorus. Then the vapours of PCl3 ared distilled and are collected in receivers cooled by water.
P4 + 6Cl2 → 4PCl3
- Phosphorus trichloride is a precursor to PCl5 and a few other phosphorus compounds, which is used in many applications, including herbicides, insecticides, oil additives, flame retardants, etc.
- It is used directly as a reagent in organic synthesis.
- It is mainly used for making phosphorus oxychloride by oxidizing it with oxygen.
- It is also used during electrodeposition of metal on rubber.
- It is also used for making pesticides, surfactants, gasoline additives, plasticizers, dyestuffs, textile finishing agents, germicides, medicinal products, and other chemicals
The compound is highly toxic. It is fatal if swallowed or inhaled. Upon prolonged exposure, it causes damage to organs. Contact with the compound causes severe skin burns and eye damage.
It is used in gasoline additives, and textile finishing, and to make chemicals, pesticides, etc.
The inorganic compound is prepared industrially by the reaction of chlorine with white phosphorus, using phosphorus trichloride as the solvent.
The compound has covalent bonding between P+3 and Cl– ions.
More on Inorganic Compounds