Naphthalene is a white solid crystal with strong odor of coal tar,
density 1.14 g/cm3, melting point 80.26 ̊C (176 ̊F).
It is soluble in water. It is flammable, and a possible carcinogen.
Azulene is an isomer of Naphthalene, with dark blue color, density 1.04g/cm3, melting point 100 ̊C (212 ̊F).
It is insoluble in water, and soluble in organic solvents.