| abstract |
The present invention can provide an aqueous composition comprising:(A) a fluoride ion supply source in an amount that gives a fluoride ion concentration of 0.05-30 mmol/L in the composition;(B) a cation supply source in an amount that gives a mole ratio of cations of 0.3-20 to the fluoride ions in the composition; and(C) 0.0001-10 mass% of one or more kinds of compounds selected from a C<sub>4-13</sub> alkylphosphonic acid, a C<sub>4-13</sub> alkylphosphonate ester, a C<sub>4-13</sub> alkyl phosphate and a salt thereof, with respect to the total amount of the composition,wherein pH is in a range of 2-6. |