Those Properties of CMAs We Know Something About

New tools are nowadays available to solve the crystallographic structure of complex compounds in metallic alloy systems and a vivid interest manifests itself to discover new compounds in multi-constituent alloys with hundreds or more atoms per unit cell. Meanwhile, it is observed that the metallic character of the alloy progressively disappears with increasing the number of atoms in the unit cell. This contribution focuses at a few examples of this atypical behavior of complex metallic alloys, including quasicrystals as the ultimate state of structural complexity in a crystal made of metals. Emphasis is put on surface properties.