Metal

A metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as opposed to nonmetallic materials which do not. Metals are typically ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing).

A metal may be a chemical element, such as iron, an alloy, such as stainless steel, or a molecular compound, such as polymeric sulfur nitride. The general science of metals is called metallurgy, a subtopic of materials science; aspects of their electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry, as it is a multidisciplinary topic. In colloquial use, materials such as steel alloys are referred to as metals, while others, such as polymers, wood, or ceramics are nonmetallic materials.

A metal conducts electricity at a temperature of absolute zero, which is a consequence of delocalized states at the Fermi energy. Many elements and compounds become metallic under high pressures; for example, iodine gradually becomes a metal at a pressure between 40 and 170 thousand times atmospheric.

When discussing the periodic table and some chemical properties, the term metal is often used to denote those elements which in pure form and at standard conditions are metals in the sense of electrical conduction mentioned above. The related term metallic may also be used for types of dopant atoms or alloying elements.