The effect of cations in a reaction mixture for the preparation of the Preyssler‐Jeannin‐Pope type 30‐tungsto‐5‐phosphate [P5W30O110Na]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, [P2W18O62]6–. Amongst all the alkali cations, only Na+ allows formation of the Preyssler‐type polyanion [P5W30O110Na]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 [P2W18O62]6–, whereas K+, Rb+, and Cs+ selectively result in the Keggin‐type polyanion [PW12O40]3–. An improved synthetic procedure for the Na+‐encapsulated Preyssler‐ion leading to a higher isolated yield is presented. Furthermore, addition of Ca2+ and Bi3+ compounds allows formation of the Ca2+‐ and Bi3+‐encapsulated Preyssler‐type polyanions, [P5W30O110Ca]13– and [P5W30O110Bi]12–, respectively. Furthermore, single‐crystal XRD structure of the Bi3+‐encapsulated Preyssler‐type polyanions, [P5W30O110Bi]12–, is presented for the first time.

We describe the preparation of ε-Keggin-type cobaltomolybdate-based 3D frameworks with sodium cations, NaH[ε-CoMoMoOCo], and their characterization by high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy. Atomic-scale HAADF-STEM images of ε-Keggin compounds were obtained for the first time, and positions of Mo and Co were confirmed. Furthermore, clear evidence of the presence of a CoO tetrahedron was obtained by X-ray absorption near-edge structure (XANES) analysis. Their characterization clearly revealed that ε-Keggin-type cobaltomolybdate units, [ε-CoMoO], constructed by a central CoO tetrahedron and 12 surrounding MoO octahedra, are linked with Co to form 3D frameworks.

We report the synthesis of multi-Mo-substituted Preyssler-type phosphotungstates, [P 5 W 30-x Mo x O 110 Na(H 2 O)] 14À , with different amounts of incorporated Mo via the hydrothermal reactions of H 3 PO 4 , Na 2 WO 4 , and Na 2 MoO 4 ; and characterization by 31 P nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), elemental analysis, electrospray ionization-mass spectrometry (ESI-MS), and cyclic voltammetry. The number of substituted Mo increases by increasing the amount of Na 2 MoO 4 in the reaction mixture, and in the [P 5 W 30-x Mo x O 110 Na(H 2 O)] 14À , up to penta-Mo-substituted species can be produced as mixtures of isomers with different Mo numbers and Mo positions. Single crystal X-ray structure analysis and density functional theory calculation indicate that the most suitable substitution position is the belt position.

The effect of metal cations in reaction mixtures for the preparation of the title anion is investigated leading to large scale (27g) synthesis of (IV) with improved yield, and the encapsulation of Ca 2+ and Bi 3+ . Compound (VII) crystallizes in the orthorhombic space group Pnma with Z = 4 (single crystal XRD). -(HAYASHI, A.; HAIOKA, T.; TAKAHASHI, K.; BASSIL, B. S.; KORTZ, U.; SANO, T.; SADAKANE*, M.; Z. Anorg. Allg. Chem. 641 (2015) 15, 2670-2676, http://dx.