Topological and geometrical characterisation of solids

Zeolites and related microporous solids are three-dimensional four-connected nets where knots are tetrahedral atoms (Si,Al,P,Ge,...). A surprise comes when by only considering a few combination rules, more than 140 different materials have been characterised to this date, and hypotethical structures (that could be synthesised) are virtually countless. A part of the secret of this amazing variety comes from the flexibility of T-O-T angles, and so different topologies can -by deforming from equilibrium of dense structural binding shown by quartz and others- can be accommodated with reasonable strain that does not break the structure. In fact all the microporous structures are quite stable. Characterisation of new structures comes from two points: topology and bond angles and distances. An automated way of calculating all these many data from the unit cell was lacking and a fortran code for this purpose has been developed by our group (in collaboration with Julian Gale). 'zeoTsites', as our code is called calculates all the necessary data and shows the results in an orderly and elegant format so that the special features of each structure are catched at a glimpse. More on this can be seen in this web page (zeoTsites: a software tool for zeolites).