A UNIVERSAL STRUCTURE-BASED CLASSIFICATION OF INORGANIC MICROPOROUS MATERIALS. F. Liebau, Mineralogisches Institut der Universitt Kiel, D-24098 Kiel, Germany

For zeolites and zeolite-like microporous materials, without regard of the type of coordination polyhedra, (tetrahedra octahedra, pyramids etc.) forming their hosts, a systematic classification is proposed. The classification is based on the structure and chemistry of their hosts, h, and the structure of their pores, p, and, in addition, to structure and chemistry of their guest species, g.

Primary classification parameters are:

CN(_ceH): coordination number of the central atom, _ceH, of the polyhedra

(primary building units) from which the host is built by sharing common peripheral atoms, _peH.

_hD : dimensionality of the host,

_pD : dimensionality of the pores,

_ceH, _peH : chemical character of the central and peripheral host atoms,

z : atomic ratio (n(_peH) / (n(_ceH).

Further subdivision can be made with regard to: (i) host structure by use of fundamental building units (fundamental chains, rings or composite polyhedra), and (ii) pore structure by use of pore width (measured in ring periodicity, P^r, or in ).

Following this scheme, each inorganic microporous material can be characterized by a Five Parameter Key:

                     CN(ceH)  hD   pD      ceH ; peH  z    
                                                           
e.g. clathrasils     4        3    0       Si ; O     2    
                                                           
       APOs          4, 5, 6  2,   ( hD    Al, P ; O  2    
                              3                            
                                                           
       synth.        4,7      3    1         Te2- ;   1.6  
CsAg5Te3                                   Ag+        7