What are the three allotrophic forms of sulphur? How are they obtained?

Question

Three allotropic forms and the temperature used to obtain the allotropic forms of sulphur

Answer 1

The three allotropic forms of sulphur are Rhombic sulphur, Monoclinic sulphur, Plastic sulphur.

1. Rhombic Sulphur:

• Stable form of a sulphur at room temperature
• It consists of lemon yellow crystals that melts at 112.8^oC

2. Monoclinic Sulphur:

• It is heated in a china dish until it melts
• The molten sulphur is cooled to the room temperature and two holes are pierced in the crust.
• The liquid is poured out on removing the crust needle like crystals of sulphur are found.

3. Plastic Sulphur:

• When sulphur is heated, plastic sulphur melts at 119^oC and a clear yellow mobile liquid is obtained
• If the substance is heated further to 160^oC, it produces a thick viscous liquid.
• If the hot liquid sulphur is poured into a cold water, it produces a soft, sticky rubber-like material. This material is called plastic sulphur.