Intermetallics and solid solution

[kelvin490]

For some systems, discrete intermediate compounds rather than solid solutions may be found on the phase diagram, and these compounds have distinct chemical formulas; for metal–metal systems, they are called intermetallic compounds. e.g. Mg₂Pb has 33 at% Pb

For binary isomorphous system like copper-nickel, if we get 33 at% Ni, can we say it is Cu₂Ni? How to distinguish intermetallics from other solid solution with same ratio?

 

[Astronuc]

For some systems, discrete intermediate compounds rather than solid solutions may be found on the phase diagram, and these compounds have distinct chemical formulas; for metal–metal systems, they are called intermetallic compounds. e.g. Mg₂Pb has 33 at% Pb

For binary isomorphous system like copper-nickel, if we get 33 at% Ni, can we say it is Cu₂Ni? How to distinguish intermetallics from other solid solution with same ratio?

Usually, if the crystal structure of the predominant element is unchanged, then it is considered a solid solution. Intermetallic compounds are often distinct or separate phases, with a different crystal lattice/structure, e.g., a bcc or fct phase in fcc or hcp lattice.

We may refer to second phase particles.