sheet with the apical sites vacant) or (for a trioctahedral site with the apical sites vacant; M represents a divalent ion such as ferrous iron or magnesium) The combined TOT layer has a residual negative charge, since its bulk composition is or . The remaining negative charge of the TOT layer is neutralized by the interlayer cations (typically sodium, potassium, or calcium ions).

Because the hexagons in the T and O sheets are slightly different in size, the sheets are slightly distorted when they bond into a TOT layer. This breaks