If the middle portion were horizontal, it would indicate either the formation of a compound or of two immiscible solid solutions.
Absorption of gas occurs, but at a certain concentration the solid solution can separate into two immiscible solid solutions.
They are unassimilable and immiscible without rapid degeneracy.
It was like the mixture of two immiscible liquids—oil, for instance, shaken up with water.
immiscible im·mis·ci·ble (ĭ-mĭs'ə-bəl)
Incapable of being mixed or blended, as oil and water.
Incapable of being mixed or blended together. Immiscible liquids that are shaken together eventually separate into layers. Oil and water are immiscible. Compare miscible.