aqueous composition comprised of iron chloride disclosed in japanese patent publication of 190226 1984 derived from iron chloride ii showed an antirusting effect only at certain salt concentrations the following examples illustrate the present invention more specifically it should be understood that the present invention is not limited to the examples alone 100 mg of the compound of reference example 5 was dissolved in 10 l of distilled water ph 6 5 at room temperature and the obtained solution was diluted 100 times using the above distilled solution to yield the objective aqueous composition 100 mg of the compound of reference example 2 was dissolved in 10 l of distilled water ph 6 0 at room temperature and the obtained solution was diluted 1000 times using the above distilled solution to yield the objective aqueous composition 100 mg of the compound of reference example 1 was dissolved in 10 l of distilled water ph 5 5 at room temperature and the obtained solution was diluted 1000 times using the above distilled solution to yield the objective aqueous composition in 100 ml of aqueous solution 10 mm of cacl 2 was dissolved 270 mg of fecl 3 6h 2 o and the resulting solution was diluted with distilled water to yield a diluted solution concentration of the salts 10 u2212 10 mm to 20 ml of the above diluted solution was added 1 g of crystalline fecl 3 6h 2 o and the solution was gradually concentrated in a porcelain dish over a boiling water bath the obtained solid concentrate was dried over p 2 o 5 in a desiccator the.