CAS number
- 118-74-1
Molecular formula
- C6Cl6
Formula weight
- 284.8 g/mol
Family
- Chlorobenzenes
Compound properties list|
| Melting/boiling point | 228 °C | Solid |
| Relative density | 2.05 g/cm3 | Sinks in water |
| Vapour pressure | 1 x 10 -5 mm Hg | Very low volatility |
| Vapour density | 0 | N/A |
| Solubility in water | 0.01 mg/L | Very low solubility |
| Henry's law constant | 1 x 10-3atm·m3/mol | Moderately volatile when dissolved |
| log Koc (Depending on soil or sediment characteristics) | 2.7 - 6.0* | Strong adsorption to organic matter |
At 20 0C, hexachlorobenzene is a solid with very low volatility and solubility. Once it is
dissolved, it is moderately volatile and adsorbs strongly to organic matter. When present in the
soil, it volatilizes and dissolves very slowly. In the dissolved phase, hexachlorobenzene can reach
the water table or drain into a waterway, where it will be diluted, before partially volatilizing.
Fragments of hexachlorobenzene can also be carried into waterways where they will be deposited at
the bottom and dissolve very slowly. Once the source has been removed, the adsorbed phase will take
a long time to disappear, slowly liberating contamination in either the gaseous or dissolved state.
The resulting plumes (gaseous and dissolved) are generally small in size.
In Canada, hexachlorobenzene is considered "toxic", as defined under Paragraph 64(a) of
CEPA 1999, and has been added to Schedule 1.
Hexachlorobenzene has not been used commercially in Canada since 1972. Hexachlorobenzene
may enter the environment from incomplete combustion of chlorinated compounds including mirex,
kepone, chlorobenzenes, pentachlorophenol, PVC, polychlorinated biphenyls and chlorinated
solvents.
In addition, hexachlorobenzene may enter the environment as a reaction by-product in
the production of carbon tetrachloride, dichloroethylene, hexachlorobutadiene, trichloroethylene,
tetrachloroethylene, pentachloronitrobenzene and vinyl chloride monomer.
Hexachlorobenzene is a fungicide formerly used as a seed treatment, especially on wheat to control
the fungal disease bunt. It has been banned globally under the Stockholm Convention on Persistent
Organic Pollutants.
