Pentachlorocyclopropane is a chlorinated cyclopropane with the chemical formula . It is a colourless liquid with a faint minty odour.[1] It is thermally unstable above 100 °C; decomposition gives 1,1,3,3,3-pentachloropropene by isomerisation.[2] Pentachlorocyclopropane can be obtained by the addition of dichlorocarbene into trichloroethylene in presence of a base.[3] Pentachlorocyclopropane itself gives tetrachlorocyclopropene when reacted with a base such as potassium hydroxide by means of dehydrohalogenation.[4]