Allotropes of Sulfur
Sulfur (S) is second only to carbon in the number of known allotropes formed. The existence of at least twenty-two sulfur allotropes has been demonstrated.
Sulfur forms an extensive series of generally yellow crystalline allotropes, Sn (where species with n up to 30 have been identified).
Orthorhombic Sulfur [ S8 ]
The most common form, stable at room temperature and atmospheric pressure. Eight sulfur atoms bond covalently in crownlike rings.
Cyclohexasulfur or Rhombohedral Sulfur [ S6 ]
Cyclohexasulfur was first reported in 1891. It is the densest of the sulfur allotropes and forms air-sensitive orange-red crystals containing chair-shaped, six-membered rings.
Amorphous Sulfur [ S ]
The result of very rapid cooling of very hot sulfur.
Disulfur [ S2 ]
The simplest allotrope of sulfur, it is a violet colour. It does not occur naturally at room temperature and pressure. It is commonly generated in the vapour generated from sulfur at temperatures above 700'C.
It has been detected by the Hubble Space Telescope in volcanic eruptions on Jupiter's satellite, Io.
See Also
Allotrope.