The S–S bond lengths are equal, at about 2.05 Å. Octasulfur crystallizes in three distinct polymorphs: rhombohedral, and two monoclinic forms, of which only two are stable at standard conditions.

Octasulfur forms several allotropes: α-sulfur, β-sulfur, γ-sulfur, and λ-sulfur.

λ-Sulfur is the liquid form of octasulfur, from which γ-sulfur can be crystallised by quenching.

Octasulfur easily forms large crystals, which are typically yellow and are somewhat translucent.

It is the main (99%) component of elemental sulfur, which is recovered from volcanic sources and is a major product of the Claus process, associated with petroleum refineries.