Laves phases are intermetallic phases that have composition AB₂ and are named for Fritz Laves who first described them. The phases are classified on the basis of geometry alone. There are three different classification classes: cubic MgCu₂ (C15), hexagonal MgZn₂ (C14), and hexagonal MgNi₂ (C36). The latter two classes are unique forms of the hexagonal arrangement, but share the same basic structure. In general, the A atoms are ordered as in diamond, hexagonal diamond, or a related structure, and the B atoms form tetrahedra around the A atoms for the AB₂ structure. Laves phases are of particular interest in modern metallurgy research because of their abnormal physical and chemical properties. Many hypothetical or primitive applications have been developed. However, little practical knowledge has been elucidated from Laves phase study so far. A characteristic feature is the almost perfect electrical conductivity, but they are not plastically deformable at room temperature.