Certain chemical elements have the ability to exist in two or more different structural forms known as allotropes. These allotropes may possess different physical properties such as density and melting points. Allotropic elements include carbon, tin, phosphorus and sulphur. Each allotrope is stable within a certain range of temperature and pressure only, and under certain conditions an allotrope can be converted into another.
The existence, especially in the solid state, of two or more crystalline or molecular structural forms of an element.
The property whereby certain elements may exist in more than one crystal structure.
The property possessed by certain elements to exist in two or more distinct forms that are chemically identical but have different physical properties. In the case of iron the crystal structure has one form at room temperature and another at high temperature. When heated above 910°C the atomic structure changes from body centered cubic to face centered cubic but reverts again when cooled. The allotropy of iron modifies the solubility of carbon, and it is because of this that steel can be hardened.
Allotropy (Gr. allos, other, and tropos, manner) is a behaviour exhibited by certain chemical elements: these elements can exist in two or more different forms, known as allotropes of that element. In each different allotrope, the element's atoms are bonded together in a different manner.