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Raman spectra of copper(I), silver(I) and gold(I) cyanides in aqueous solutions of sodium thiosulphate
Author(s) -
ElHinnawi Mahmoud A.,
Peter Lyle,
Meyer B.
Publication year - 1985
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250160410
Subject(s) - aqueous solution , chemistry , raman spectroscopy , copper , inorganic chemistry , nuclear chemistry , organic chemistry , physics , optics
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 S 2 O 3 2− ratio, forming only mixed cyanothiosulphate species. No evidence was found for the formation of Cu (CN) 2 − , Cu(CN) 3 2− or Cu(CN) 4 3− . 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 S 2 O 3 2− ratio, resulting in the formation of Ag(CN) 2 − and Ag(S 2 O 3 ) 2 3− species. As the concentration of thiosulphate increases Ag(CN) 2 (S 2 O 3 ) 3− and Ag(CN) 2 (S 2 O 3 ) 2 5− are formed. There is strong evidence for the existence of bridging silver thiosulphate complex in solutions of low S 2 O 3 2− concentration. AuCN dissolves completely in aqueous thiosulphate solution in a 1:2 AuCN to S 2 O 3 2− ratio, forming Au(CN) 2 − , Au(CN) (S 2 O 3 ) 2− and Au(S 2 O 3 ) 2 3− . No evidence was found for the formation of species of higher coordination number on increasing the concentration of S 2 O 3 2− , which indicates that the linear two‐coordinate gold complexes are the most stable.