The relaxation rate ratio method (RRR) has been used to calculate molecular correlation times, tau(c), from the C-13 and Cd-113 relaxation rates of cadmium-cyclohexanediamine tetraacetate (CyDTA). The ratio of spin-spin (R-2) relaxation rates to spin-lattice (R-1) relaxation rates (R-2/R-1) is used to determine the relative motion of specific nuclei within the Cd-CyDTA complex. Formation of the Cd-CyDTA complex results in an increase in the measured NMR rotational correlation times compared with the values obtained for the CyDTA ligand alone. C-13 chemical shifts, evidence of Cd-113-N-14 coupling and NMR rotational correlation times provide information concerning the geometry of the Cd-CyDTA complex. The NMR experimental results correlate with anhydrous, hydrated, and hydroxylated ab initio structures of the Cd-CyDTA complex.