Raman spectra of copper(I), silver(I) and gold(I) cyanides in aqueous solutions of sodium thiosulphate

Abstract

Systems of copper(I), silver(I) and gold(I) cyanides dissolved in aqueous solutions of sodium thiosulphate in different molar ratios have been studied by Raman Spectroscopy. CuCN dissolves completely in aqueous thiosulphate solution in a 1:3 CuCN to S2O32− ratio, forming only mixed cyanothiosulphate species. No evidence was found for the formation of Cu (CN)2−, Cu(CN)32− or Cu(CN)43−. The mixed cyano copper complex was isolated as a white solid insoluble in water and most other solvents. The solid probably consists of a polymeric structure with bridging cyanide and thiosulphate. AgCN dissolves completely in aqueous thiosulphate solution in a 1:1 AgCN to S2O32− ratio, resulting in the formation of Ag(CN)2− and Ag(S2O3)23− species. As the concentration of thiosulphate increases Ag(CN)2(S2O3)3− and Ag(CN)2(S2O3)25− are formed. There is strong evidence for the existence of bridging silver thiosulphate complex in solutions of low S2O32− concentration. AuCN dissolves completely in aqueous thiosulphate solution in a 1:2 AuCN to S2O32− ratio, forming Au(CN)2−, Au(CN) (S2O3)2− and Au(S2O3)23−. No evidence was found for the formation of species of higher coordination number on increasing the concentration of S2O32−, which indicates that the linear two‐coordinate gold complexes are the most stable.

Electrochemistry and speciation of Au+in a deep eutectic solvent: growth and morphology of galvanic immersion coatings

“…45 In contrast, AuCN was readily soluble in Ethaline 200 due to the presence of coordinating species as a component of the bulk liquid. Accordingly, the FT of the AuCN solution data, Figure 3 (b), displays three distinct peaks, which could be fitted to a mixed coordination of both Cl − and CN − , in a 1:1 ratio.…”

Photodegradation of Azathioprine in the Presence of Sodium Thiosulfate

“…The doublet’s separation was 1.2 eV and the peaks were constrained to a 2:1 area ratio during fitting. The bands at 162.1–163.3 eV and 168.1–169.3eV are attributed to Na 2 S 2 O 3 compounds, as stated in the literature [ 28 , 32 ]. The bands at 166.4–167.6 eV are attributed to the Na 2 SO 3 compound, while the bands at 169.4–170.6 eV are ascribed to Na 2 SO 4 , as also highlighted in the Na1s spectrum [ 28 , 33 ].…”

“…These Raman lines are not far from those reported by M.A. El-Hinnawi et al at 330–360, 430–450, 530, 670, 1000–1010 and 1125–1140 cm −1 , which were associated with the vibrational modes of free S 2 O 3 2− , symmetric S-S stretching, anti-symmetric S-O bending, symmetric S-O bending, symmetric S-O stretching and anti-symmetric S-O in free S 2 O 3 2− [ 28 ]. The Raman lines of AZA are shown in Table 2 [ 14 , 29 , 30 ].…”

Disinfestation of historical buildings – corrosion evaluation of four fumigants on standard metals

“…For EDN fumigant, a gas impact is also observed. For silver treated with EDN, small sharp bands for M-CN and CN vibrations respectively at 300-350 and 2135 cm −1 [42] are present ( Fig. 7), probably linked to the unattributed reduction peak found at about -0.6 V/MSE (Fig.…”