A Quasi-Intramolecular Solid-Phase Redox Reaction of Ammonia Ligands and Perchlorate Anion in Diamminesilver(I) Perchlorate
Lara Alexandre Fogaça,
Laura Bereczki,
Vladimir M. Petruševski,
Berta Barta-Holló,
Fernanda Paiva Franguelli,
Miklós Mohai,
Kende Attila Béres,
Istvan E Sajó,
Imre Miklós Szilágyi,
Laszlo Kotai
Affiliations
Lara Alexandre Fogaça
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
Laura Bereczki
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
Vladimir M. Petruševski
Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, 1000 Skopje, North Macedonia
Berta Barta-Holló
Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovi´ca 3, Novi Sad 21000, Serbia
Fernanda Paiva Franguelli
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
Miklós Mohai
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
Kende Attila Béres
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
Istvan E Sajó
Szentagothai Research Centre, Environmental Analytical and Geoanalytical Research Group, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
Imre Miklós Szilágyi
Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Muegyetem rakpart 3, H-1111 Budapest, Hungary
Laszlo Kotai
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
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.
