Calculations of 29Si MAS NMR chemical shift from silicate mineral structure

A simple correlation has been found between 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) chemical shift and molecular geometry that is applicable to all silicate minerals. It is based on the magnetic anisotropy and valence of the bond between the oxygen and the second-neighbour cation to the silicon. The equations can be used to calculate the chemical shift and hence can be applied to assess the validity of structural models.