Bisilicate

n. (Min. Chem.) A salt of metasilicic acid; -- so called because the ratio of the oxygen of the silica to the oxygen of the base is as two to one. The bisilicates include many of the most common and important minerals. [ 1913 Webster ]

n.[ Cf. F. silicate. ] (Chem.) A salt of silicic acid. [ 1913 Webster ]

☞ In mineralogical chemistry the silicates include; the unisilicates or orthosilicates, salts of orthosilicic acid; the bisilicates or metasilicates, salts of metasilicic acid; the polysilicates or acid silicates, salts of the polysilicic acids; the basic silicates or subsilicates, in which the equivalent of base is greater than would be required to neutralize the acid; and the hydrous silicates, including the zeolites and many hydrated decomposition products. [ 1913 Webster ]