Hume-Rothery rules

Hume-Rothery rules is a set of empirical guideliness that help explain and predict solid solubility of one element in another in metallic alloys.

Size Factory: Elements that have a size diferrence of less than 15% can form solid solutions

Valence Electrons: Elements with similar valence electron structures are more likely to form solid solutions.

Crystal Structure: Similar structures promote solid solubility.

Eletronegativy: Elements with similar eletronegativy tend to form solid solution. Otherwise form an ionic bound beetween elements.

Valence: Elements with the same or similar, not more than one unit.

Lattice Constant: Elements with similar lattice constants (the distance between atom in a crystal lattice) are more likely to form solid solutions. A close match in lattice constants reduce lattice strain when atoms substitute for each other.

Electronic Structure:  Elements with  similar eletronic structures have a higher tendency to form solid solutions.