In 13C[1H] NMR spectra of liquids, one observes a single resonance for each symmetrically nonequivalent carbon atom. The same is true of the 13C CPMAS spectra of solids. The difference is that the molecular symmetry is the determining factor in liquids NMR whereas the crystallographic symmetry is the determining factor in solids NMR. As a result, solids NMR can give different spectra for different solid polymorphs and multiple resonances due to multiple nonequivalent molecules in the asymmetric unit of the crystal structure. The figure below compares the solids 13C CPMAS and liquids 13C[1H] NMR spectra of a vitamin C (ascorbic acid) tablet.