Effects of the orientation of the 23Na-29Si dipolar vector on the dipolar mediated heteronuclear solid state NMR correlation spectrum of crystalline sodium silicates

► D-HMQC spectra with quadrupolar nuclei are affected by the relative orientation of the quadrupolar tensor and the dipolar vector. ► 23Na-29Si D-HMQC experiments help separate the contributions of crystalline phases in sodium silicates. ► Ab initio calculations of the NMR parameters confirm the assignment made with D-HMQC experiments.