Solid State Chemistry

Inorganic Chemistry - Body-Centered Cubic Diagram

Solid state chemistry categorizes elements as solids, ionic solids, and alloys by their lattice structures and unit cell packing. There are seven different types of lattice structures that may be formed:

 

 

  • Cubic
  • Tetragonal
  • Orthorhombic
  • Hexagonal
  • Rhombohedral
  • Monoclinic
  • Triclinic

The basics of descriptive inorganic chemistry do not go too in depth on this area. However, it is useful to know generally what each of these lattice structures are in case they are referred to.

There are four key ways a unit cell can be packed are:

  • Simple cubic
  • Body-centered cubic
  • Face centered cubic
  • Hexagonal close packing

These four unit cells listed above are in order of least to most efficient use of space. The simple cubic unit cell wastes roughly 40% to 50% of the space within the unit cell while the hexagonal close packing wastes around 20% to 30% of the space within the unit cell. Both the face centered cubic and hexagonal close packing are ideal lattice structures due to their high efficiency in regards to usage of space in the unit cell.