Lanthanide derivatives of Ta/W mixed-addendum POMs as proton-conducting materials.

Four lanthanide derivatives of Ta-containing POMs [Ln3(H2O)22][P2W15Ta3O62]·nH2O (Ln = La, 1; Ce, 2; Pr, 3; and Nd, 4) were isolated by the self-assembly of Wells-Dawson type Ta/W mixed-addendum POM and lanthanide ions. Compound 1 showed excellent proton conduction performance at high relative humidities (RHs), with conductivity reaching 1.26 × 10-2 S cm-1 at 95 °C under 98% RH.