Question

What is the polymorphic form of Sulphur ?

Answer 1

The polymorphism may be defined as the ability of a solid material to exist in more than one form or different crystal structure. Sulphur exists in two forms - Rhombic sulphur and Monoclinic sulphur. These two are interconvertible forms.

Complete answer:
First, let us discuss polymorphism.
The word polymorphism means the ability of a solid material to exist in more than one form or different crystal structure. Many elements, polymers, minerals etc. exhibit polymorphism.
The Sulphur also exhibits polymorphism. The polymeric form of sulphur is ${S_8}$. It can exist in two forms -
The first one is Rhombic sulphur (α- sulphur)
The second one is Monoclinic sulphur (β- sulphur)
Both these forms of sulphur are interconvertible with change in temperature. For ex- If we heat the rhombic sulphur above 369 K, it will give us monoclinic sulphur.
The Rhombic sulphur is crystalline in nature and has an octahedral shape. It has yellow coloured crystals. It has a specific gravity of 2.06. It is not soluble in water. But is soluble in benzene, ether alcohol etc.
Monoclinic sulphur is colourless and has needle shaped crystals.

Note:
It must be noted that the temperature 369 K is known as transition temperature. At this temperature, both the forms of sulphur are stable. There are various uses of sulphur such as in vulcanization of rubber, as bleaching agent or in formation of carbon disulphide.