Ca[Si₂O₂N₂]—A Novel Layer Silicate

A corrugated [Si2O2N2]2− layer anion, which is constructed of dreier rings, forms the basis of the silicate Ca[Si2O2N2] (see picture). The unusual structure results from the fact that every N atom—unlike the O atoms in oxosilicates—links three neighboring Si tetrahedron centers within the layers, whereas all the O atoms are exclusively bonded terminally to the Si atoms.