A Quasi-Intramolecular Solid-Phase Redox Reaction of Ammonia Ligands and Perchlorate Anion in Diamminesilver(I) Perchlorate

The reaction of ammoniacal AgNO3 solution (or aq. solution of [Ag(NH3)2]NO3) with aq. NaClO4 resulted in [Ag(NH3)2]ClO4 (compound 1). Detailed spectroscopic (correlation analysis, IR, Raman, and UV) analyses were performed on [Ag(NH3)2]ClO4. The temperature and enthalpy of phase change for compound...

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Bibliographic Details
Published in:Inorganics 2021-05, Vol.9 (5), p.38
Main Authors: Fogaça, Lara Alexandre, Bereczki, Laura, Petruševski, Vladimir M., Barta-Holló, Berta, Franguelli, Fernanda Paiva, Mohai, Miklós, Béres, Kende Attila, Sajó, Istvan E, Szilágyi, Imre Miklós, Kotai, Laszlo
Format: Article
Language:English
Subjects:
ammine
Ammonia
Anions
Aqueous solutions
Chlorate
Chlorine
Correlation analysis
disproportionation
Enthalpy
Infrared analysis
Intermediates
Ligands
Nitrates
perchlorate
Perchloric acid
Phase transitions
redox reaction
Redox reactions
Silver
Silver chloride
Silver nitrate
Sodium perchlorate
Solid phases
Thermal decomposition
vibrational spectroscopy
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Summary:The reaction of ammoniacal AgNO3 solution (or aq. solution of [Ag(NH3)2]NO3) with aq. NaClO4 resulted in [Ag(NH3)2]ClO4 (compound 1). Detailed spectroscopic (correlation analysis, IR, Raman, and UV) analyses were performed on [Ag(NH3)2]ClO4. The temperature and enthalpy of phase change for compound 1 were determined to be 225.7 K and 103.04 kJ/mol, respectively. We found the thermal decomposition of [Ag(NH3)2]ClO4 involves a solid-phase quasi-intramolecular redox reaction between the perchlorate anion and ammonia ligand, resulting in lower valence chlorine oxyacid (chlorite, chlorate) components. We did not detect thermal ammonia loss during the formation of AgClO4. However, a redox reaction between the ammonia and perchlorate ion resulted in intermediates containing chlorate/chlorite, which disproportionated (either in the solid phase or in aqueous solutions after the dissolution of these decomposition intermediates in water) into AgCl and silver perchlorate. We propose that the solid phase AgCl-AgClO4 mixture eutectically melts, and the resulting AgClO4 decomposes in this melt into AgCl and O2. Thus, the final product of decomposition is AgCl, N2, and H2O. The intermediate (chlorite, chlorate) phases were identified by IR, XPS, and titrimetric methods.
ISSN:2304-6740
2304-6740
DOI:10.3390/inorganics9050038