Synthesis and Structural Characterization of Lanthanide‐Containing Polytungsto‐antimonate [{Sb 3 (µ 3 ‐O) 2 Ln(H 2 O)Ln(H 2 O) 2 } 2 (SbW 10 O 37 ) 2 (SbW 8 O 31 ) 2 ] 22 – Molecules Deriving from the Decomposition of the [Sb 8 W 36 O 132 ] 24 – Macroanion

Reaction of the tungsto‐antimonate [Sb 8 W 36 O 132 ] 24– polyoxometalate with late trivalent lanthanide cations (from Gd to Lu) gives rise to the formation of eight isostructural molecular compounds [{Sb 3 (µ 3 ‐O) 2 Ln(H 2 O)Ln(H 2 O) 2 (SbW 10 O 37 )(SbW 8 O 31 )} 2 ] 22– (Ln = Gd III ( 1 ), Tb III ( 2 ), Dy III ( 3 ), Ho III ( 4 ), Er III ( 5 ), Tm III ( 6 ), Yb III ( 7 ), Lu III ( 8 )). All compounds were characterized by routine solid‐state techniques (IR spectroscopy, TGA, single‐crystal X‐ray diffraction) and, by SAXS measurements in aqueous solutions to assess their stabilities. Luminescent properties of compounds 5 and 7 were also studied.