Abstract
Effective use of the interstices of inorganic host structures is the key to develop new functional materials. The interstices in layer structured crystals are most versatile; the reaction concerning the interlayer space is called intercalation. Some examples of new functional materials developed using interstices are briefly reviewed, such as clay-organic complexes, porous pillared materials, interlayer grafting, anion exchangeable compounds, and layer structured nitride superconductors. A new silicon clathrate superconductor with a Si-sp3 cage structure is also introduced.