Salts of Phosphonic Acid Derivatives: Illustrative Examples of Solid State NMR Spectroscopy

High-resolution solid state C, Na and P NMR data have been obtained for the acid form and for several salts of the phosphonic acids: ethane-1,2-diphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid (HEDP), and 3-amino-1-hydroxypropane-1,1-diphosphonic acid. The data provide evidence by which sample purity and crystallinity may be examined and from which the size of the asymmetric unit may be determined. In the case of the sodium salts of ethane-1,2-diphosphonic acid, the P and Na spectra provide evidence of possible motion or bond fluctionality for the phosphonic acid group.