Orientation of tensorial interactions determined from two-dimensional NMR powder spectra

Methods are described for determining the mutual orientation of molecular interaction tensors based on two-dimensional NMR powder spectra. Necessary conditions are derived under which this determination can be made, procedures for the computation and analysis of 2D powder spectra are indicated and a technique for the construction of ridge plots is worked out. Chemical shift resolved dipolar powder spectra provide an easily interpreted representation of the mutual orientation of chemical shielding and dipolar coupling tensors. The various features and practical applications of such spectra are demonstrated with 2D powder spectra of benzene, lead formate, and methyl formate.