Sulphur

Sulphur, S, is a yellow nonmetallic main group element belonging to the Group VIb of the periodic table. Although sulphur is in the same group in the periodic table as oxygen, there are more differences in the chemical characteristics of these elements than there are similarities. Thus, while oxygen always displays a valency of two, sulphur displays valences of four (in sulphur dioxide, SO2), six (in thionyl chloride, socl2) and eight (in sulphur hexafluoride, SF8).

In the elemental state, sulphur exists in polymeric forms.

Sulphur is an essential element for living organisms, and is present in some amino-acids.


Discovery


Occurrence


Extraction


Preparation


Properties

Sulphur occurs in a large number of allotropic forms in the solid state. Several liquid forms are also known.

Rhombic Sulphur

Rhombic Sulphur which is also known as Octahedral Sulphur or alpha-Sulphur, is a yellow crystalline solid, which crystallises from a solution in carbon disulphide. X-ray investigation shows this form to consist of eight sulphur atoms in the molecule in a ring structure.

Monoclinic Sulphur

Monoclinic Sulphur which is also known as Prismatic Sulphur or beta-Sulphur, is a yellow crystalline solid, which is obtained by allowing molten sulphur to solidify, when long prismatic needles form on the walls of the container that can be separated from the still molten liquid by pouring off the latter. X-ray investigation shows this form to consist of eight sulphur atoms in the molecule in a ring structure, but arranged within the crystal in a different manner to that in rhombic sulphur.

Plastic Sulphur

Plastic Sulphur which is also known as gamma-Sulphur, is a tough elastic substance that is formed when molten sulphur is poured into cold water. On standing it slowly crystallises.

Amorphous Sulphur

Amorphous Sulphur is the insoluble white amorphous solid that remains when flowers of sulphur are extracted with carbon disulphide.

Colloidal Sulphur

Colloidal Sulphur which is also known as delta-Sulphur, is a yellow crystalline solid.

Reactions


Uses

Sulphur is an important industrial raw material which is used


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