Copper(II) sulfate is one such system where multiple crystalline hydrates have had their terahertz spectra fully assigned, and the unique spectral fingerprints of the forms allows for characterization of multicomponent systems with relative ease. Terahertz vibrational spectroscopy has evolved into a powerful tool for the detection and characterization of transition metal sulfate compounds, specifically for its ability to differentiate between various hydrated forms with high specificity. Uncovering the Terahertz Spectrum of Copper Sulfate Pentahydrate. The high covalence of the Cu sites in CuSO( 4) was found to be

The covalent radicalization of ligands similar to sulfate, with consequent energy redistribution of the virtual orbitals, represents a new mechanism for the induction of ligand preedge XAS features. Similar XAS fits indicated 2% sulfur 3p character for the preedge transition orbitals in and SO( 4)].

From pseudo-Voigt fits to the CuSO( 4) sulfur K-edge XAS spectrum, a ground-state 3p character of 6% was quantified for the orbital contributing to the preedge transition, in reasonable agreement with the DFT calculation. It is this redistribution, rather than a direct covalent interaction between Cu(II) and sulfur, that is the origin of the observed sulfur XAS preedge feature. Both experimental and computational results indicated that the high covalence of anhydrous CuSO( 4) has made sulfate more like the radical monoanion, inducing an extensive mixing and redistribution of sulfur 3p-based unoccupied orbitals to lower energy in comparison to sulfate in ZnSO( 4). Hybrid density functional calculations on the two most realistic models of the covalent delocalization pathways in CuSO( 4) indicate about 50% electron delocalization onto the sulfate oxygen-based 2p orbitals however, at most 14% of that can be found on sulfate sulfur. Copper L-edge XAS of CuSO( 4) revealed that 56% of the Cu(II) 3d hole is delocalized onto the sulfate ligand. Preedge features in the XAS spectra of transition metal ligands are generally attributed to covalent delocalization of a metal d-orbital hole into a ligand-based orbital. Similar but weaker preedge features occur in the sulfur K-edge XAS spectra of (2478.

Sulfur K-edge X-ray absorption spectroscopy (XAS) of anhydrous CuSO( 4) reveals a well-resolved preedge transition feature at 2478.8 eV that has no counterpart in the XAS spectra of anhydrous ZnSO( 4) or copper sulfate pentahydrate. Szilagyi, Robert K Frank, Patrick DeBeer George, Serena Hedman, Britt Hodgson, Keith O High covalence in CuSO 4 and the radicalization of sulfate: an X-ray absorption and density functional study.

Cuso4 molar mass