ABSTRACT
In this chapter, we will consider the crystal structure of most
metallic elements, nonmetals from column IV of the periodic
table, and noble gases. Arsenic and selenium from columns V and
VI, respectively, are also included in our analysis. More than 30
elements crystallize in two monoatomic crystal structures, fcc and bcc, at room temperature and normal pressure. There are also a large number of elements that crystallize in a structure that can be
described by a hexagonal Bravais lattice but with two-atom basis.
This is the so-called hexagonal close-packed (hcp) crystal structure. To describe this structure, identical spheres are arranged in a
regular array to minimize the interstitial volume. This close-packing
of spheres may lead, however, to many different arrangements. One
of them turns out to be nothing more than the fcc structure. Under normal conditions, more than 40% of the elements crystallize in the
hcp, fcc, and other close-packed crystal structures. All of them will be considered in this chapter.
