Silicate ion (SiO₃²⁻)
- Charge
- −2
- Atoms
- Si, O × 3
- Atoms in total
- 4
- Mass of the ion
- 76.082 g/mol
This silicate ion, also called metasilicate, is one silicon atom with three oxygen atoms and a 2− charge. Silicon is in the +4 state, and three oxygens at −2 each bring the total to −2. In nature, silicate units link into chains, sheets and frameworks that make up most of the rock, sand and clay in Earth’s crust, as well as glass and cement.
- Silicon also forms orthosilicate, SiO₄⁴⁻, the four-oxygen building block of most silicate minerals.
- In solids, SiO₃²⁻ is usually the repeating unit of a long chain, as in the pyroxene minerals, rather than a small separate ion.
- Sodium metasilicate, Na₂SiO₃, is a common form of water glass and is used in detergents and cements.