Silicic acid

Silicic acid /sɪˈlɪsɪk ˌæsɪd/ is a chemical compound. Silicic acid is the general name for a family of chemical compounds containing the element silicon attached to oxide and hydroxyl groups. This family of compounds have the general formula [SiO_x(OH)_4-2x]_n. Some simple silicic acids have been identified, but only in very dilute aqueous solution, such as metasilicic acid (H₂SiO₃), orthosilicic acid (H₄SiO₄, pK_a1=9.84, pK_a2=13.2 at 25 °C), disilicic acid (H₂Si₂O₅), and pyrosilicic acid (H₆Si₂O₇); however in the solid state these probably condense to form polymeric silicic acids of complex structure.