Abstract: The effects of various kinds of sodium carboxylates such as glycollate(NaGly), tartrate（Na2Tart）, citrate（Na3Cit） and the disodium of EDTA(Na2EDTA) on the phase compositions of calcium oxalate (CaC2O4) were studied in aqueous solution and X-ray powder diffraction was used to characterize the products. The results are all showed in Table 1. It can be seen that in the presence of sodium carboxylates, the percentages of the calcium oxalate monohydrate (COM), dihydrate (COD) and trihydrate (COT) in the crystals depend on the concentration of the carboxylates. In lower concentration range only COM was precipited. In higher concentration range COD and COT were induced. The ability to inhibit the formation of COM but favor that of COD and COT follows the order: Na3Cit >Na2Tart >Na2EDTA >NaGly. So citrate is considered to be an effective inhibitor of curing urolithiasis. Our study can give a reference for clinical therapy.

Key words: Calcium oxalate, Urinary stone, Sodium carboxylates, Biomineralization