Related Experiment Video
Updated: Aug 19, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
[Spectral study of three compounds of tungstosilicic salt with Keggin structure]
Yi-ping Chen1, Shi-long Zhao, Han-hui Zhang
1Depatment of Chemistry, Fuzhou University, Fuzhou, China.
Abstract:
Three compounds of tungstosilicic acid and tungstosilicic salt: K3H[SiW(VI)12O40].3H2O(I), (H3O)4[H3SiW(VI)9W(V)3O40].2H2O(II) and [(CH3)4N]4[SiW(VI)12O40].4.5H2O(III), with Keggin structure, have been synthesized. The relationship between their properties and structures was studied by using FTIR, NIR FT-Raman, UV-Vis and flurescence etc. They possess isolated [SiW12O40] cage anion, which combines with cation and water by static electric action and weak hydrogen bond; The study of their FTIR and Raman spectra shows that the vibrational frequencies of the group are related to the structure of the materials. For the compound II, the vibrational frequency of vas(W=Od) decreases as part of W6+ are reduced to W5+, and the charges of anion group affect vas(W-Oc-W), vas(Si-Oa) and delta(Oa-Si-Oa) etc. apparently. In UV-Vis spectra of compound I and II, there are two characteristic peaks at 200 and 260 nm, respectively. The fluorescence spectra of compound I were studied, and showed that the emission peak is at 350, 440, 520 and 675 nm excited by 220, 350 and 440 nm.
Related Concept Videos
Valence Bond Theory
UV–Vis Spectroscopy: Woodward–Fieser Rules
VSEPR Theory and the Basic Shapes
UV–Vis Spectroscopy: Molecular Electronic Transitions
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Mass Spectrum: Interpretation

