Sodium pyrosilicate
Sodium pyrosilicate is the chemical compound. It is one of the sodium silicates, specifically a pyrosilicate, formally a salt of the unstable pyrosilicic acid.Structure
The anhydrous solid has the triclinic crystal structure, with space group Å, b = 11.5811 Å, c = 23.157 Å, α = 89.709°, β = 88.915°, γ = 89.004°, V = 1555.1 Å3, Z = 8, Dx = 2.615 g·cm−3, μ. The anions are arranged in layers parallel to the plane, with the sodium cations distributed in 24 distinct crystallographic positions, coordinated by 4 to 6 near oxygen atoms. Some of the 4-coordinated sodium atoms can be interpreted as parallel columns of edge-sharing tetrahedra. The columnar arrangement forms tunnels that house the remaining sodium cations. Twinning at a microscopic scale simulates a much larger monoclinic C centered lattice.
