Two Members of the {X₄Nb₁₆O₅₆} Family (X = Ge, Si) Based on [(GeOH)₂Ge₂Nb₁₆H₂O₅₄]^12– and [K(GeOH)₂Ge₂Nb₁₆H₃O₅₄]^10–

Abstract

Two new heteropolyniobate compounds, (C2N2H10)6[(GeOH)2Ge2Nb16H2O54]·25H2O (1) and [Cu(en)2(H2O)2]5K10[K(GeOH)2Ge2Nb16H3O54]2·38H2O (2, en = ethylenediamine), have been prepared under hydrothermal–conventional combination conditions and structurally characterized by elemental analysis, IR spectroscopy, powder and single‐crystal XRD, diffuse reflection spectroscopy, and thermogravimetric (TG) analysis. Compounds 1 and 2 are based on [(GeOH)2Ge2Nb16H2O54]12– and [K(GeOH)2Ge2Nb16H3O54]10– building blocks, respectively. Compound 1 represents the initially isolated Nb/Ge lacunary derivative and compound 2 exhibits 1D ladderlike chains. The photoluminescence properties and electrochemical properties of compounds 1 and 2 have been investigated.

A Vanadogermanate Dimer‐Based Chain with Magnetic and Luminescent Properties

“…The UV/Vis diffuse reflectance spectrum of 1 shows intense absorption bands in the range λ = 200 to 400 nm (Figure S4), which are mainly attributed to oxide‐to‐metal (O→V) charge‐transfer transitions . In the visible region, the broad band at λ = 500–800 nm is assigned as an intervalence charge‐transfer band (V IV →V V ) …”

Tailored Ordered Structures with Functional Units of Distorted [NbO6] and Antiparallel [GeO4] for Enhanced Birefringence in Germanate Crystal

“…Specifically, the absorption peaks observed at ≈470, 410, and 783 cm −1 are corresponding to the asymmetric stretching of [GeO 4 ] tetrahedra, [ 36,37 ] whereas the characteristic peaks located at 694 and 645 cm −1 are mainly caused by the bridging Nb‐O‐Nb vibration. [ 38,39 ] These observations are in good agreement with those of the structural characteristics of CNGO.…”