web >. The atoms in a crystal are in a regular repeating pattern called the crystal lattice... A crystal lattice is defined by a repeated three-dimensional unit... The basic building block of these crystalline structures is known as the "unit cell" and this "unit cell" repeats itself over and over to form a lattice... When a pure metal starts to form from a cooling molten state, the atoms arrange themselves in an ordered geometrical pattern that is repeated over and over again producing a crystalline structure.

web >. Crystalline solids such as metals consist of a regular, three dimensional arrangement of atoms in a periodic pattern called a crystal lattice. In each type of crystal structure a certain fundamental grouping of atoms is repeated indefinitely in three dimensions. This is called a unit cell. There are several types of crystals o Molecular crystals o Infinite arrays: SS Metallic crystals SS Ionic crystals SS Continuous covalent crystals web > Metals possess a crystal lattice structure.

As mentioned previously, metals are composed of atoms that have some weakly bound valence electrons. As these atoms come together to form the crystal lattice, some of the weakly bound electrons are freed from their atoms by the energy released in binding. In very good conductors such as copper, aluminium and silver, all the atoms are fully ionized, one electron becoming detached from each nucleus in the lattice. These de localised valence electrons are free to move from atom to atom and are thus shared by all atoms in the lattice. In this sense, they behave like a gas, an "electron gas." Thus, there are many valence electrons available for conduction in metallic solids. Conduction in metals can be considered as a free movement of electrons, relatively unimpeded by the crystal lattice..