In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula [SiO(4-2x)− 4−x] n, where 0 ≤ x < 2. The family includes orthosilicate SiO4− 4 ( x = 0 ), metasilicate SiO2− 3 ( x = 1 ), and pyrosilicate Si2O6− 7 ( x = 0.5, n = 2 ).