Bismuth(III)‐Containing Heteropolytungstates [Bi(XW11O39)2]n– (X = Si, Ge, n = 13; X = P, n = 11) and [Bi(P2W17O61)2]17–

We report on the synthesis and structural characterization of four bismuth(III)‐containing sandwich‐type heteropolytungstates with Bi in 8‐coordination. The three isostructural Keggin‐type ions [Bi(α‐XW 11 O 39 ) 2 ] n – {X = Si ( 1 ), Ge ( 2 ), n = 13; X = P ( 3 ), n = 11} and the Wells–Dawson‐type ion [Bi(α 2 ‐P 2 W 17 O 61 ) 2 ] 17– ( 4 ) were prepared via simple one‐pot synthetic procedures in aqueous medium. The novel polyanions comprise a Bi 3+ ion linking two monolacunary {XW 11 } or {X 2 W 17 } units in a sandwich‐type fashion. The Bi 3+ ion is coordinated by four oxygens of each monolacunary POM unit, resulting in 8‐coordination with square‐antiprismatic geometry. Such a coordination mode is rare for Bi 3+ .