Rhombic Sulphur:
It is an allotropic form of sulphur which is stable below 96. One molecule of rhombic sulphur contains 8 atoms, i.e., 8 gm. The crystal of rhombic sulphur has octahedral structure.
Monoclinic Sulphur:
It is the allotropic form of sulphur which is stable between 96 to 119. A molecule of monoclinic sulphur consists of eight sulphur atoms, i.e., 8 gm, but is different from rhombic sulphur in the arrangement of atoms.
Plastic Sulphur:
It is a non-crystalline allotropic form of sulphur, it can be stretched like a rubber, it is unstable and changes into rhombic sulphur on slight heating. Even at room temperature, it changes.