The invention relates to a composition of a carboxyl-functionalized silicon-containing precursor compound of at least two different organic acids, said composition having two, three, or four carboxyl groups functionalized with various hydrocarbon groups according to formula I and/or II. Said carboxyl groups can be released as carboxylic acids and can be used as silane hydrolysis catalysts and/or silane condensation catalysts. The invention further relates to methods for producing the composition, to the use of the composition for cross-linking polymers, and to a formulation of the composition in the form of a masterbatch.