Homogeneous ice nucleation temperatures (T(H)s) of aqueous alkali halide solutions were measured as a function of salt concentration. Cationic effect on T-H increases with decreasing ionic radius: Cs+ < Rb+ < K+ < Na+ < Li+ while anionic effect becomes larger with increasing ionic radius: Cl- < Br- < I-. There is almost a linear relation between T-H and 1/r(+) (or 1/r(-)) for the same halide (or alkali) solutions up to high salt concentrations (r(+) and r(-) are ionic radii of alkali and halide ions, respectively). (C) 2002 Elsevier Science B.V. All rights reserved.