Phosphorus pentachloride

 

Phosphorus pentachloride

Chemical formula	PCl5
OTP appearance	crystals pale yellow
Molar Mass(g/mol)	208.22
Density(g/cc)	2.1
Melting Point(°C)	160.5
Boiling Point(°C)	166.8
Solubility in water(g/L)	reacts
Immediate Danger to Life and Health	70mg/m3
NFPA 704	0 3 2 W

Uses

Justification Questioned

Other

• Common and potent chlorinating agent
• Chlorination of carboxylic acids

  CH₃COOH + PCl₅ → CH₃COCl + PCl₃ + HCl

Natural occurrence

• Does not occur naturally

Production

Synthesis

1. Expose white or red phosphorus to chlorine, in excess, producing first a mixture of phosphorus trichloride and phosphorus pentachloride:

   P₄ + 8 Cl₂₂PCl₃ + 2 PCl₅

2. Continue to add chlorine in great excess, converting the -trichloride to -pentachloride

   2 PCl₃ + 2 Cl₂ → 2 PCl₆

See Also

• phosphorus trichloride
• phosphorus oxychloride