THE NOTION OF STRUCTURE IN MODERN CHEMISTRY .2. STRUCTURAL VARIETY OFCONDENSED PHASES - GENERALIZED CRYSTAL-CHEMISTRY

The structural variety of condensed phases with crystalline (c) or qua sicrystalline (q) or complete/partial disorder (d) is represented as a triangular diagram. The c, q, or d characteristic refers to one of th e three dimensions so that the type of condensed phase is denoted by t hree symbols (ccc is the ideal crystal; cqd is a phase where disorder is combined with crystalline and quasicrystalline orders). Comparative studies of various condensed phases with data extrapolation to other states is termed generalized crystal chemistry.