Sodium metasilicate, also known as soda glass, is an inorganic substance with the chemical formula Na₂SiO₃. Its aqueous solution is called water glass, available in colorless, greenish, or brown solids or thick liquids. It is widely used in foundry, papermaking, sand casting, re-molding, paper tube and box adhesives, construction, carbon black, subway construction, gold and silver foil lamination, ceramics, and alkali for sol-gel silicones, among others. It can also be customized into various liquid sodium metasilicate products according to customer requirements.