Mono‐ and Di‐Lanthanide Derivatives of 22‐Tungsto‐2‐antimonate(III), [ Ln (H 2 O) 4 Sb 2 W 21 O 72 (OH)] 10– and [ Ln 2 (H 2 O) 8 Sb 2 W 20 O 70 )] 8–

Abstract. The mono‐lanthanide‐containing [ Ln (H 2 O) 4 Sb 2 W 21 O 72 (OH)] 10– ( Ln = Yb ( 1 ), Lu ( 2 )), and the di‐lanthanide‐containing [ Ln 2 (H 2 O) 8 Sb 2 W 20 O 70 )] 8– ( Ln = Yb ( 3 ), Lu ( 4 ), Y ( 5 )) have been synthesized in aqueous‐acidic media and characterized in the solid state. Polyanions 1 and 2 were prepared by reaction of Ln 3+ ions with [Sb 2 W 22 O 74 (OH) 2 ] 12– ( Sb 2 W 22 ), whereas 3 – 5 were prepared by using the trilacunary 9‐tungstoantimonate(III) [ B‐α‐ SbW 9 O 33 ] 9– ( SbW 9 ). Polyanions 1 – 5 crystallized as sodium salts in the triclinic system, space group P $\bar{1}$ . All compounds were characterized in the solid state by FTIR, single‐crystal XRD, TGA, and elemental analysis. Polyanions 1 – 5 contain the lacunary [Sb 2 W 20 O 70 ] 14– unit ( Sb 2 W 20 ), which is coordinated to either a lanthanide and a tungsten ion, leading to a structure with C s symmetry in polyanions 1 and 2 , or to two lanthanide ions, leading to a structure with idealized C 2 h symmetry, in polyanions 3 – 5 .