solid-solid reaction

A solid-solid reaction, also known as a synthesis, occurs when two or more solid substances combine to form a new solid substance. This process is represented by a chemical equation, where reactants are transformed into products. For example, iron (Fe) and sulfur (S) can react to form iron sulfide (FeS), symbolized as Fe(s) + S(s) → FeS(s).1

A solid solution is a mixture of two crystalline solids that form a new crystalline solid with a combined crystal lattice. This can be achieved by melting and cooling the solids or by depositing their vapors. The properties of these solid solutions can be adjusted by altering the proportions of the constituent substances, making them valuable in applications like semiconductors for electronic and optical devices.2