An intermetallic (also called intermetallic compound, intermetallic alloy, ordered intermetallic alloy, long-range-ordered alloy) is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties. They can be classified as stoichiometric or nonstoichiometic intermetallic compounds. 
Although the term "intermetallic compounds", as it applies to solid phases, has been in use for many years, Hume-Rothery has argued that it gives misleading intuition,  suggesting a fixed stoichiometry and even a clear decomposition into species.