At room temperature and atmospheric pressure, propene is a gas, and as with many other alkenes, it is also colorless with a weak but unpleasant smell.[1]
Propene has a higher density and boiling point than ethylene due to its greater mass. It has a slightly lower boiling point than propane and is thus more volatile. It lacks strongly polar bonds, yet the molecule has a small dipole moment due to its reduced symmetry (its point group is Cs).
Propene has the same empirical formula as cyclopropane but their atoms are connected in different ways, making these molecules structural isomers.