Large singly charged ions, with low charge density (for example, SCN-, H2PO4-, HSO4-, HCO3-, I-, Cl-, NO3-, NH4+, Cs+, K+, (NH2)3C+ (guanidinium) and (CH3)4N+ (tetramethylammonium) ions; exhibiting weaker interactions with water than water with itself and thus interfering little in the hydrogen bonding of the surrounding water), are chaotropes whereas small or multiply-charged ions, with high charge density, are kosmotropes (for example, SO42-, HPO42-, Mg2+, Ca2+, Li+, Na+, H+, OH- and HPO42-, exhibiting stronger interactions with water molecules than water with itself and therefore capable of breaking water-water hydrogen bonds).b Kosmotropes remain hydrated near the water surface, while the chaotropes lose their hydration sheath