Synthesis of silicoaluminate geopolymers
Geopolymer Chemistry: an overview

Scientists and engineers with a background in mineralogy and geochemistry, continue to use geometric patterns of coordination with oxygen, in the form of tetrahedron, pentahedron or hexahedron fits. It is explained that the lattice of silicoaluminate-based geopolymers consists of SiO₄ and AlO₄ tetrahedra associated by their vertices consisting of oxygen atoms (figure 4). Cations (Na⁺, K⁺, Li⁺, Ca²⁺, Ba²⁺, H₃O⁺) are present in the lattice cavities to balance the negative charge of Al³⁺ in IV coordination.