Physical and Chemical Properties

In commercial uses, PCBs are often mixed with organic solvents such as chlorinated benzenes. Other mixtures also combine differently chlorinated PCBs together; each unique PCB component in a mixture is called a congener.

Physical properties
- density at 30°C = 1.4 - 1.5 g/mL (denser than water)
- low water solubility, but high solubility in organic solvents
- invisible vapour
- bitter odour
- high heat capacity
- slippery
- average boiling point for solid PCBs = 340 - 375°C
- most are liquid at SATP




Chemical properties
- flash point = 141°C
- non-corrosive
- low flammability, making PCBs non-explosive
- low conductivity, making them electrically insulating
- chemically stable and resistant to decomposition
- high thermal resistance: a temperature of 1200 °C is required in order to completely destroy them


Patterns of PCB properties
Lower chlorinated PCBs are thin, light-coloured liquids. As more chlorine atoms are added to the compound, the liquid becomes darker and more viscous. The highest chlorinated PCBs are yellow or black waxy solids.

PCBs with fewer chlorine atoms exhibit higher water solubility and greater flammability. They are also less stable and lipophilic. Monochlorinated and dichlorinated biphenyls are less hazardous than those with a higher degree of chlorination.