1,3-Cyclohexadiene

1,3-Cyclohexadiene is an organic compound with the formula (CH2)2(CH)4. It is a colorless, flammable liquid. Its refractive index is 1.475 (20 °C, D). A naturally occurring derivative of 1,3-cyclohexadiene is terpinene, a component of pine oil. [1,3-Cyclohexadiene. Wikipedia]