(g) Variation of the solid structure expression
Many solid-state inorganic compounds have complicated three-dimensional
structures. Different structural illustrations for the same compound help our
understanding of its structure. In the case of complicated inorganic compounds, drawing
bond lines between atoms, as in most organic compounds, causes confusion. The anions
in many metal oxides, sulfides, or halides form tetrahedra or octahedra around the central
metal cations. Although there is no bond between anions, the structures are greatly
simplified if they are illustrated by the anion polyhedra sharing apexes, edges, or faces. In
such illustrations, cationic metal atoms are usually omitted. As has been mentioned, ionic
solid structures can be thought of as a close packed arrays of anions.