Ionic-nonionic dihydrophilic block copolymers with poly(ethylene glycol) as nonionic blocks and phosphorylated polyglycidol as ionic blocks of various lengths and various degrees of phosphorylation were prepared. The influence of these variables on the CaCO3 crystal structure and the inhibition of crystal growth was studied. The best results (small crystal size, low dispersity of sizes, and longest inhibition time) were observed for limited degrees of phosphorylation. A certain part of the dihydrophilic block copolymers was permanently bound to the formed particles, opening a way to the synthesis of inorganic-organic (polymer) hybrids based on these components. (c) 2006 Wiley Periodicals, Inc.