Sulphur exists in four allotropic forms,

(1) Rhombic or octahedral or α-sulfur : It is a bright yellow solid, soluble in CS₂ and stable at room temp. All other varieties of sulfur gradually change into this form on standing.

(2) Monoclinic sulphur or prismatic or ß-sulfur: It is prepared by melting the sulfur and then cooling it till a crust is formed. On removing the crust, needle shaped crystals of monoclinic sulfur separate out. It is dull yellow in color, soluble in CS₂ and stable only above 369K. Below this temperature it changes into rhombic form.

Thus, at 369K both these varieties co-exist. This temperature is called transition temperature and the two sulfurs are called enantiotropic substances. It also exist as molecules similar to that of rhombic sulfur but the symmetry of the crystals is different.

(3) Plastic or amorphous or y -sulfur :It is a super cooled liquid insoluble in CS₂ , soft and amorphous. It consists of long zig-zag chains of S-atoms.