Table 1.

Biophysical characteristics of common cations^a

Cation	Atomic weight	Ionic radius (126, 127) (Å)	Hydrodynamic radius (126, 127) (Å)	Mobility in H2O (126, 127) (10−4 cm2 s−1 V−1)	TiH2O (126, 128)
Li+	6	0.060	1.73	4.01	0.33
Na+	23	0.095	1.67	5.19	0.39
NH4+	18	0.133	1.14	7.60	0.49
K+	39	0.143	1.14	7.62	0.49

^aReferences, where applicable, are in parentheses in column headers.