Durene
Durene, or 1,2,4,5-tetramethylbenzene, is an organic compound with the formula C6H2(CH3)4. It is a colourless solid with a sweet odor. The compound is classified as an alkylbenzene. It is one of three isomers of tetramethylbenzene, the other two being prehnitene (1,2,3,4-tetramethylbenzene, m.p. −6.2 °C) and isodurene (1,2,3,5-tetramethylbenzene, m.p. −23.7 °C). Durene has an unusually high melting point, reflecting its high molecular symmetry.