section_path: Characteristics/Physical properties
section_name: Physical properties
paragraph_text: Physical properties
  
  Sulfur forms several polyatomic molecules. The best-known allotrope is octasulfur, cyclo-S. The point group of cyclo-S is D and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless. It melts at 115.21 °C (239.38 °F), boils at 444.6 °C (832.3 °F). At 95.2 °C (203.4 °F), below its melting temperature, cyclo-octasulfur begins slow changing from α-octasulfur to the β- polymorph. The structure of the S ring is virtually unchanged by this phase change, which affects the intermolecular interactions. Cooling of molten sulfur gives freezing point in 119.6 °C (247.3 °F), as it predominantly consists of the β-S molecules. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased viscosity due to the formation of polymers. At higher temperatures, the viscosity decreases as depolymerization occurs. Molten sulfur assumes a dark red color above 200 °C (392 °F). The density of sulfur is about 2 g/cm, depending on the allotrope; all of the stable allotropes are excellent electrical insulators.
  
  Sulfur sublimes more or less between 20 °C (68 °F) and 50 °C (122 °F).
  
  Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene.