Q.What is the difference between allotropy and polymorphism ?

Step 1. Define allotropy. Allotropy is the existence of an element in two or more different structural/bonding forms while remaining in the same physical state -- for example O2 and O3 (both gases), or rhombic and monoclinic sulfur (both solids, though at different temperature ranges).

Step 2. Define polymorphism. Polymorphism is the more general phenomenon of a substance -- element OR compound -- existing in more than one crystal structure; it is commonly used for solid-state variants obtained under different temperature/pressure conditions, and does not require every polymorph to be equally stable at room temperature. …

Comparing the scope of each term: allotropy is element-specific and same-physical-state; polymorphism is the broade …

• Treating the two terms as fully interchangeable; allotropy is really a special case that applies only to elements. …