SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE, AND REPLACEMENT REACTIONS OF COORDINATED WATER MOLECULES OF [(CeO)3(H2O)2(AsW9O34/)2]12-.

(CeO)3(AsW9O34)2ċ2H2O12- was synthesized by the reaction of A-AsW9O349- with Ce(IV). The product was well characterized by IR, UV, 183W NMR spectra and elemental analyses. The structure of K5Na4H3[(CeO)3(H2O)2-(AsW9O34)2]ċ11H2O has been solved by X-ray diffraction. The structure comprises a belt of three oxygen atoms alternating with the three cerium atoms encapsulated between two fragments of the trivacant Keggin polyanions A-AsW9O349-. Its structure is similar to that of the analogue phosphorus derivative. The experimental results show that many ligands, [Fe(CN)6]4-, [Fe(CN)6]3-, SO32-, SCN-, etc. can replace the coordinated water molecules in aqueous solution resulting in characteristic colors of the solutions. [ABSTRACT FROM AUTHOR]