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.

Two new YIII containing sandwich‐type heterometallic tungstophosphates: [Y{PM2W10O38(H2O)2}2]11– (M = CoII (1) and ZnII (2)) have been synthesized under mild reaction conditions. Both the molecular complexes 1 a and 2 a were synthesized by reacting Y(NO3)3⋅6H2O, M(NO3)2⋅6H2O (M = CoII and ZnII) with Wells‐Dawson type divacant K14[P2W19O69(H2O)]⋅24H2O precursor. The potassium salts of single crystalline material were collected and further used for characterization with different analytical techniques including single crystal X‐ray diffraction (SC‐XRD), Fourier transform infrared (FT‐IR) spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP‐AES), 31P, 183W and 89Y nuclear magnetic resonance (NMR) spectroscopy, high‐resolution electro‐spray ionization mass spectrometry (HR‐ESI‐MS) as well as thermogravimetric analysis. Single crystal X‐ray diffraction analysis shows that both polyanions crystallize in the orthorhombic crystal system with space group Iba2. Each polyanion consists of (1,5) isomer of di‐metal substituted α‐Keggin type tungstophosphates, which sandwiched a YIII ion.