is a mixture of metals
or a mixture of a metal and another element
. Alloys are defined by metallic bonding character. An alloy may be a solid solution
of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic
compounds are alloys with a defined stoichiometry
and crystal structure. Zintl phases
are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle
for information on classifying bonding in binary compounds).