| any of certain amorphous gelatinous masses, formed when alkaline silicates are treated with acids, which dissociate readily into silica and water. |

| silicic acid n. A jellylike substance, H2SiO3, produced when sodium silicate solution is acidified. |
silicic acid
a compound of silicon, oxygen, and hydrogen, regarded as the parent substance from which is derived a large family-the silicates-of minerals, salts, and esters. The acid itself, having the formula Si(OH)4, can be prepared only as an unstable solution in water; its molecules readily condense with one another to form water and polymeric chains, rings, sheets, or three-dimensional networks that constitute the structural units of silica gel (q.v.) and many minerals that have very low solubility in water.
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