High Temperature Behaviour of Polyoxometalates Containing Lanthanides

Abstract

The possibility of a simple heating process of POM to obtain tungsten bronze was investigated for nuclear waste immobilisation via DTA/TG and high temperature XRD. Heating process up to 900 o C caused the decomposition of structure for both systems. Cooling process seemed to have little effect on the final product for the K 11 [Nd (PW 11 O 39 ) 2 ]·xH 2 O, whereas the cooling profile showed a significant effect on the K 13 [Nd(SiW 11 O 39 ) 2 ]·xH 2 O. Nd formed two types of tungsten bronzes, namely Nd 2 WO 6 and Nd 4 W 3 O 15 in K 11 [Nd(PW 11 O 39 ) 2 ]·xH 2 O and K 13 [Nd(SiW 11 O 39 ) 2 ]·xH 2 O, respectively.