How does sulfur has atomicity 8 [duplicate]

How does sulfur has atomicity 8, when its valence electrons are 6 like oxygen- ie even 2 sulfur atoms can share a pair of electrons and achieve the octet rule, why should it involve 8 atoms?

marked as duplicate by Martin - マーチン♦, bon, ron, Klaus-Dieter Warzecha, tschoppiJun 19 '15 at 18:54

Octasulfur is just one of few different allotropic forms of sulfur. It happens to be the most stable form at room temperature, but different conditions favor different forms. Thus, for instance, sulfur vapor usually contains $\ce{S, S2, S4, S6, S8}$, and the higher the temperature, the lower is the amount of $\ce{S8}$ molecules since they break up into smaller allotropes of sulfur.