Silica/alkali ratio dependence of the microscopic structure of sodium silicate solutions

► The SiO2:Na2O ratio dependence of the structure of water glass is revealed. ► Small silica clusters and monomers dominate at the lowest ratios (3.3-3.8). ► Fractal particles and larger structures are present at higher ratios (>4). ► A too high electrolyte concentration causes the instability region, around ratio 4.