Cation Effect on Formation of Preyssler‐type 30‐Tungsto‐5‐phosphate: Enhanced Yield of Na‐encapsulated Derivative and Direct Synthesis of Ca‐ and Bi‐Encapsulated Derivatives

Abstract The effect of cations in a reaction mixture for the preparation of the Preyssler‐Jeannin‐Pope type 30‐tungsto‐5‐phosphate [P 5 W 30 O 110 Na] 14– is investigated. Reaction of phosphate and tungstate with a P/W ratio of ca. 3.9 in an acidic aqueous solution without cations selectively leads to the Dawson‐type 18‐tungsto‐2‐phosphate, [P 2 W 18 O 62 ] 6– . Amongst all the alkali cations, only Na + allows formation of the Preyssler‐type polyanion [P 5 W 30 O 110 Na] 14– , with an encapsulated Na + ion, and the product yield can be improved by increasing Na + amount. The presence of Li + ions instead results in the Dawson‐type polyanion [P 2 W 18 O 62 ] 6– , whereas K + , Rb + , and Cs + selectively result in the Keggin‐type polyanion [PW 12 O 40 ] 3– . An improved synthetic procedure for the Na + ‐encapsulated Preyssler‐ion leading to a higher isolated yield is presented. Furthermore, addition of Ca 2+ and Bi 3+ compounds allows formation of the Ca 2+ ‐ and Bi 3+ ‐encapsulated Preyssler‐type polyanions, [P 5 W 30 O 110 Ca] 13– and [P 5 W 30 O 110 Bi] 12– , respectively. Furthermore, single‐crystal XRD structure of the Bi 3+ ‐encapsulated Preyssler‐type polyanions, [P 5 W 30 O 110 Bi] 12– , is presented for the first time.