The reaction of A-PW9O9 34 with carbonate solution of lanthanide ions produces different products under the same conditions. The sandwich-type complexes of [(A-PW9O34)2(H2OM)3CO3]11 are the main products of the reaction of A-PW9O9 34 with Eu3þ and Gd3þ while, with Pr3þ and Nd3þ products are decatungstometalate complexes [(W5O18)2M]9. The products have been isolated and characterized by elemental analysis, infrared, 31PNMRspectroscopy, thermogravimetric analysis (TGA), and single crystal structure analysis. The structures of the first complexes consist of two trivacant polyoxometalates A-PW9O9 34 which are linked by a (MOH2)3CO3 belt. The 3 vibrational band of CO2 3 at 1471–1485 cm1 and a break in the TGA curves at 425C confirm the presence of coordinated CO2 3 in the structures. The single crystal structure analysis was carried out on K6Na2(H3O)[(W5O18)2Pr] 18H2O (H38K6Na2O55PrW10). The anion consists of two [W5O18]6 linked via Pr3þ. The Pr3þ is eight coordinate with overall anion symmetry close to D4d.
