Sodium silicate is a generic name for chemical compounds with the formula Na ₂ₓSi yO ₂y₊ₓ or ₓ· y, such as sodium metasilicate Na ₂SiO ₃, sodium orthosilicate Na ₄SiO ₄, and sodium borosilicate Na ₆Si ₂O ₇. The anions are often polymeric.
Sodium silicates are used primarily in detergents, paper, water treatment, and construction materials. One of the greatest uses of sodium silicate solutions is as a cement for the manufacture of cardboard.