what is allotropy?what are the various allotropic form's of sulphar
Answers
Explanation:
each of 2 or more diff. physical forms in which an element can exist
various forms of sulphur are
yellow rhombic sulphur ( alpha sulphur)
monoclinic ( bita sulphur)
Allotropy, the existence of a chemical element in two or more forms, which may differ in the arrangement of atoms in crystalline solids or in the occurrence of molecules that contain different numbers of atoms.
1) Rhombic Sulphur
We find them as yellow and translucent crystals.
Rhombic Sulphur has a melting point of 114o C.
The density of rhombic Sulphur is 2.08 g/cm3
It is stable at temperatures below 96oC.
2) Monoclinic Sulphur
These are transparent and amber crystals.
They have a melting point of 119oC.
The density of monoclinic sulphur is 1.98 gcm3
It is unstable at temperatures below 96oC and changes into rhombic form.
We must remember that at a temperature of 96oC or above, rhombic sulphur changes to kaleidoscopic or prismatic sulphur. At 96oC or beneath, kaleidoscopic or prismatic sulphur changes to rhombic sulphur.
These allotropes that alter their configuration from one form to another by a change in the temperature are Enantiotropic Allotropes.
3) Colloidal Sulphur
We can produce this sulphur by passing hydrogen sulphide through a saturated and cooled solution of sulphur dioxide in water. Another method is by including a solution of alcohol and sulphur in the water.
It acts as a solvent in carbon disulfide.
We utilise it as a part of medicines.
4) Milk of Sulphur
We can produce this by the action of weak hydrochloric acid on ammonium sulphide. In a similar fashion, this milk of sulphur forms by the boiling of sulphur with calcium hydroxide (aqueous solution). We filter this mixture and add weak hydrochloric acid to get the milk of sulphur.
This compound is non-crystalline and white in colour.
It is soluble in carbon disulphide.