In polycrystalline media or frozen solution, ENDOR can provide spatial relationships between the coupled nuclei and electron spins. This is possible in solid phases where the EPR spectrum arises from the observance of all orientations of paramagnetic species; as such the EPR spectrum is dominated by large anisotropic interactions. This is not so in liquid phase samples where spatial relationships are not possible. Such spatial arrangements require that the ENDOR spectra are recorded at different magnetic field settings within the EPR powder pattern.