text: Geopolymerization is the process of combining many small molecules known as oligomers into a covalently bonded network. The geo-chemical syntheses are carried out through oligomers (dimer, trimer, tetramer, pentamer) which are believed to contribute to the formation of the actual structure of the three-dimensional macromolecular framework, either through direct incorporation or through rearrangement via monomeric species. These oligomers are named by some geopolymer chemists as sialates following the scheme developed by Davidovits, although this terminology is not universally accepted within the research community due in part to confusion with the earlier (1952) use of the same word to refer to the salts of the important biomolecule sialic acid. 
  The image shows 5 examples of small oligomeric potassium aluminosilicate species (labelled in the diagram according to the poly(sialate) / poly(sialate-siloxo) nomenclature), which are key intermediates in potassium-based alumino-silicate geopolymerization. The aqueous chemistry of aluminosilicate oligomers is complex, and also plays an important role in the discussion of zeolite synthesis, a process which has many details in common with geopolymerization.
  Example of (-Si-O-Al-O-) geopolymerization with metakaolin MK-750 in alkaline medium
  It involves four main phases comprising seven chemical reaction steps: 
  * Alkaline depolymerization of the layered structure of the calcined kaolinite; 
  * Formation of monomeric and oligomeric species;
  * In the presence of waterglass (soluble potassium or sodium silicate), cyclic Al-Si structures can form (e.g. #5 in the figure), whereby the hydroxide is liberated by condensation reactions and can react again;
  * Geopolymerization (polycondensation) into polymeric 3D-networks.
  The reaction processes involving other aluminosilicate precursors, e.g. low-calcium fly ash, crushed or synthetic glasses, or natural pozzolans, are broadly similar to the steps described above.